How do I configure WRT54G as a wireless access point?

Question

Ater a whole series of problems related to Vista, a WAP54G, Airport xpress, wireless printers, etc. plus at least three hours on the phone with Linksys tech support acessing my computer remotely and still not fixing the problems, I dumped my WRT54GC for a Belkin-N router.  I set it up over the weekend and slowly regained internet access, then the pinter, then the Airports. 
I still would like to have an access point because my signal strength even with the new N router is too weak downstairs to allow my PS3 to connect to it.  I cannot figure out how to configure the WAP54G to make it work.  I want to take a shot with the WRT54GC.  From what I've read, I should be able to do it. 
I can get into the router (referring to the Linksys) no problem.  I can reconfigure it to an extent, changing the IP address to the recommended 192.168.1.2.  I do this by running an ethernet cable from my PC to the router.  Howver, after changing the IP address in the router I can't get into it any more using the new IP address.  When I attach teh Linksys router to the Belkin I can't get in either.
Both the Linksys and the Belkin use 192.168.1.1 as the default IP address for each device. 
I would like to know what settings I need to change i nteh WRT54G to turn it ino an access point -- an extenson of my existing network with teh Belkin router attached to the Comcast modem.  I have looked at various how-to's and they all seem to assume I am connecting the two routers with an ethernet cable.  If it's not clear at this point, I'd like to connect them wirelessly.
Thanks.

Answer 1

Thanks so much for the reply.
I was working with it all last night and somethign strange happened.  After reading some other info on the internets, I changed the IP address on the WRT to 192.168.2.1.  It updated, I then ran the wire from the Belkin to the WRT, I typed in 192.168.2.1, it took me to the Linksys setup page, but when I clicked "wireless" in the WRT setup, it took me to the Belkin setup page.  How in the world did that happen?
Armed with tis new info, I did a hard reset on the WRT -- assuming it would change the WRT back to 192.168.1.1 -- got into the setup, turned off DHCP, left the IP as .1.1, and then wired it again into the Belkin.  I can now get into the setup of either one.
Here's the thing:  I don't want the two routers wired together.  I want to move the WRT downstairs so a PS3 can pick up the signal.  I want the WRT to wirelessly relay that signal to the Belkin to get the PS3 onto the net.  I can't run a wire from the Belkin to the WRT. 
I've read conflicting reports about whether the  WRT can do this.  Other sites suggest adding 3rd party firmware to add that functionality but that will definitely push the bounds of my abilities and likely exceed them.  So, can the WRT even function in this way? 
Inre the WAP, I don' know why but my ability to access the setup menu via 192.168.1.245 is very hit or miss -- much miss than hit.  It makes no sense unless there is a bad connection somewhere because I hard reset, wire it to my laptop, put in the IP, and time out 19 times out of 20.  I've got the MAC address for the router, and I think I know I want it to function as a repeater, but I've not been able to get that working right eihter. 
Thanks for any further reply.