How To Setup 2 Networks - One "N" & One "G"

Question

Hi all and Happy New Year!
Basically, what I want to do is to setup 2 networks at home, one based purely on 802.11n & the other based on 802.11g.
I would probably name them as something like Home 'N' & Home 'G' in the new setup.
The reasoning behind this is that we have a number of devices, some of which are "N" capable and some of which are only "G" capable. From what I've read, if I set up the network to run in compatibility mode to allow the G clients access, the whole network slows to G speeds.
We have the following devices suffixed by what I understand are there wireless capabilities;
Imac - N (using ethernet currently)
MBP - N (wireless connection currently)
Windows Laptop x 2 - N (wireless connection currently)
XBOX 360 - N (wireless connection currently)
PS3 - ? (ethernet into AE currently)
PSP - G (I believe this is WEP only but am open to correction)
DSi X 2 - G (WEP only for Nintendo WFC connections)
Iphones - G
So what I want to do is to have the N devices connecting to the N network, and the G devices connecting to the G network, thereby allowing both networks to run at their full speeds.
In terms of equipment, I have a 500gb Time Capsule (not the new dual band version), an Airport Express (bought last year brand new), and I also have my old Netgear DG834N modem/router which can be brought out of retirement if needed.
I'm also considering purchasing another AE to use for AirTunes/network extension when I'm exercising out the back in another room. (Probably not relevant, but may require additional setup help).
Currently, the Imac is ethernet wired to the TC which is ethernet wired to an X-MODEM M3 for our internet connection. The TC is set to 802.11n in compatibility mode with b/g, and is used to backup my mbp/imac, which I'd like to keep it doing.
The AE is in the living room with the PS3 ethernet wired into it and an sp/dif optical out to the Denon Amp for AirTunes.
The AE is set to extend the existing wireless network.
Now, it may not be possible to do what I want to do with my current equipment, and if that's the case, then any suggestions as to additional requirements along with idiot-proof walkthroughs will be much appreciated!
However, if what I want to do is possible by re-jigging my current setup, then again, any and all help is much appreciated.
Thanks in advance for your help.
Rick

Answer 1

With the powerline adapters, you would plug one adapter into an AC wall socket near the Time Capsule and connect a short ethernet cable from one of the LAN <-> ports on the TC to the ethernet adapter.
Plug another powerline adapter into an AC socket near the location where you want the Airport Express (AX) and connect the AX to the ethernet adapter with a short ethernet cable.
If you go with the AX in the same room as the TC, you'll connect an ethernet cable from one of the LAN <-> ports on the TC to the AX.
The AX would be configured the same in either type of setup.
Configure the AX as follows using AirPort Utility - Manual Setup
Click the Wireless tab below the row of icons
Wireless Mode = Create a wireless network
Wireless Network Name = Your choice
Check mark next to Allow this network to be extended
Radio Mode = 802.11b/g compatible. You may need to hold down the option key on your Mac when you click on the selection box to see this choice
Security = Same as your TC is using
Password = Your choice
Confirm Password
Click the Internet icon
Connect Using = Ethernet
Connection Sharing = Off (Bridge Mode)
Update to save settings and restart both the TC and the AX
If you want the TC to do "n" only, open AirPort Utility - Click Manual Setup
Click the Wireless tab
Change the Radio Mode to 802.11n only (2.4 GHz)
Update to save settings