New to the WRT300N - Firmware & help needed

Question

Hi. First off, I apologize that this is going to be very long.  I really hope someone will take the time to read it all and give me some help.
I posted about a week ago about problems with my WRT54GS.  All of a sudden with no changes, the wireless stopped working.  I tried for a few days to fix it with no luck.  I decided to order the WRT300N (I figured if I was going to buy a new one, I'd upgrade and this is the one that Linksys recommended).
I should mention that after ordering the new router, the wireless on the old one started working again but it wasn't working normal.  The signal quality had always pretty much been excellent and now it started going up & down but at least it was staying connected.
The new router came today.  I disconnected the old one and connected the new one and everything went smoothly.  Both my wired & wireless computers worked great.  Less than an hour later, the wireless disconnected.  I went to view available networks and my network (I use our last name) was gone.  I shut off the laptop and it still didn't see the network.  So I started looking at the router settings just to be sure that nothing had changed.  About 15 minutes later, the laptop found the network and connected again.  The signal quality dropped to good and has stayed there ever since.
Just for information, when the laptop is on the desk (which it is 90% of the time), it's only about 5 feet away from the router.  I have not tried to take the laptop out of the room yet.  Also more information if it helps.  I have a large "U" shaped desk.  My monitor for my desktop sits in the middle.  On either side are the speakers.  To my left (in front of me) is a UPS (plugged into this UPS is the tower, monitor, speakers, cradle for my mouse, modem & router), then the tower (I can't put it on the floor because I have physical issues that would prevent me from accessing it there).  Now if I turn my chair to the left, the desk has an upper level.  This is where my DSL modem & the router are.  They are on the end near where the computer is on the lower level.  This is the same setup we were using before.  Old router worked great for almost 2 years with signal strength at excellant on the laptop.  It just started acting up all of a sudden.  If I go back to facing center and then turn to the right, that's where my husband's laptop sits.  The only other equipment there is a calculator and a lamp and on the floor is another UPS which has his laptop (which has an Intel wireless G card in it), a laser printer, and the above mentioned calculator & lamp plugged in.
Prior to today, I had the Logitech MX3100 keyboard & mouse set.  I had purchased a new mouse (Logitech MX Revolution).  So I was using the keyboard from the MX3100 with the new mouse and everything was fine running that way for weeks before the problem kicked in.  So I don't think it's got anything to do with the mouse.  Today's setup is a little different.  I am no longer using the MX3100 keyboard.  I am using Logitech DiNovo Edge, which uses a bluetooth dongle.  I also don't think it's any interference from this keyboard since this is a pre-existing problem.
I do have a cordless phone in the room (it's on the left hand side of the desk from where I sit at the opposite end from the modem & router...also it's one of those that doesn't need a phone line)but it's a 5.8 ghz.
The old router had the option to change the channel, etc.  This one has auto for standard channel & wide channel & there's no way to change it that I can see.  Radio band is also set to auto but does have 2 choices under it (standard & wide).  As I said before, I use our last name for our SSID.  It's the same one I've been using for years.  There is no one else around here with that SSID.  Network mode is mixed.
Concerning the firmware....the information for mine is WRT300N V1.1 firmware v1.51.2.  I tried to look for an update but the only one in the list is the WRT300N V1.0.  I did click on that but the firmware version is lower and I don't want to screw anything up.  Is there a firmware update for me or not?  If so, please point me in the right direction as I can't find it.
Concerning the signal strength....would it help to buy a new wireless card for the laptop?  The Intel card has been updated with the newest software.  The card is internal and to my knowledge can only be replaced with the same card or a bluetooth card.  (Computer is a Dell XPS M140.)  I do have a card slot but I'm confused because I think Dell called it an Express Card slot and I don't know whether or not the Linksys notebook card that is recommended for this router would work in this slot.  If the card would work, is it worth the expense?
What else can I try.  I thought about moving the router furthur to the left but it would require moving a few other items and I'm not sure if the cords are long enough.  Would it help if the router & modem were not plugged into the same UPS?  I do have a regular surge protecter near where my phone is.  I would really rather leave them plugged into the UPS though for obvious reasons.
Also if it helps, I have the router on it's side with the 2 antennas on the end pointing straight up and the flat one in the middle I have angled this way.
I hope I have given enough information for some suggestions.
Thanks,
Lisa

Answer 1

Thanks for the response.  I was wondering if anyone would take the time to read such a long post.  I wanted to be sure to try to give as much information as possible.
My desktop (Dell XPS400) tower is made out of metal...but the router is actually not sitting on it.  There is a shelf to the left of my tower (when I'm facing it, otherwise it's to the right of it).  That's where the modem & router sit.  The shelf sits about 3" over from the edge of the computer and it's about 7" above it.
As far as the wireless card for my husband's laptop...I'm still thinking about it.  I'm wondering if there would be any improvement in speed or the quality of the connection with the N card.
Now I just went into the router's settings and tried to make the changes you suggested.  I was able to change  the radio band from auto to wide BUT once I do that, I loose the ability to leave the wide channel & standard channels on auto.  The options for the wide channel are 3-9 and the standard are 1 & 5.  I don't know which ones are best to pick so for now I'm not changing anything.  I didn't change the advanced settings either as I wasn't sure if I could do that without changing the other settings first.
My husband has noted that he does see the quality of the connection occasionally jump to excellant.  For the most part it's staying on good in here.  We haven't brought it out into the living room yet to see what it does out there.  He hasn't needed to.  He has had it disconnect on him a couple of times as well.
I did forgot to mention in that book I wrote that we do live in an apartment building.  We are on the 1st floor in the back of the building.  Our office is between our living room & another bedroom.  There is an apartment above us.  There is another apartment on the other side of the other bedroom.  Our bathroom is across the hall from this room, other side of that is the kitchen and then there is an apartment in the front of the building.  Our front door is off the living room, a hallway seperates our apartment from another one.  There are 4 apartments on each floor.  Laundry (directly under us) & storage in basement.
I give all these details to try to get the best help.  I don't know if all this extra info is helpful or not.  We have been using Linksys routers for quite a few years now.  This is our 3rd one and our 2nd wireless one.  We have been in this apartment for a year now and had no trouble until a few weeks ago.  Previously lived in another apartment of the same floor plan in the same complex but on the 3rd floor (boy did we hate walking up those stairs!) with no trouble.
Looking forward to hearing back from  you so I can try to make the changes you suggested.
Thanks,
Lisa