Wireless trouble... I am pulling hair out.

Ok, I have been at this problem for a little but now, nothing is working, and I am going to beat the hell out of my brother for getting me started on this :) (maybe).

Here's the skinny;
I have my computer lab upsairs, but my nearest phone jack is downstairs. (we got DSL)
My DSL modem supports wireless, so instead of running cable down the stairs (which is what we have been doing, but I need to clean it up a little) my brother went and bought this wireless AP. (A linksys WRT45G) They both support B/G. So I go about setting this little wireless dealy up. But for some god-forsaken reason I can't get the 2 to talk to each other. I changed the channel and network name settings so they were the same (don't worry about WEP, as soon as I have this figured out, I will go for the encryption). There is no MAC address filtering on, the 2 APs have different names (instead of WRT45G it is upsairs_AP) and I turned off the DHCP server for the upstairs AP (the downstairs one still has it on) and set DHCP (on the upstairs wireless router) on so it got its IP from the DSL modem. Now, I have no idea where I am goin wrong on this... all my computers have DHCP, the 2 APs are on the same channel and have the same network name.... No MAC filtering. This linksys crap expects you to hook the internet modem up to it with wires, but that would defeat the purpose of getting it (To eliminate the wires all over) Someone, anyone. Please... I am goin bald here.

Why don't you just hook the modem into the Linksys? Are you trying to make your modem talk to the Linksys (wirelessly), and then the linksys to the computers? That won't work, afaik.

Modem ------cable----- Linksys -------wireless------- computer is what you need, not Modem ------wireless------Linksys --------wireless------computer.

As it is now:
Computers/Xbox -wired-> switch -wired-> Modem

-wired-> means wires ~wireless~> means wireless

As I want it:
Computers/Xbox -wired-> linksys wireless ~wireless~> Modem

The linksys wireless router has enough ports on the back that I don't need another switch for my 2 computers and Xbox

You'll have to put the AP's (both the Linksys and the DSL) in Bridge Mode to have them talk to each other - from what I can find, though, it often doesn't work when using two different brands. Here's how to do it with 2 Linksys AP's (it's for the WAP54G, but should be similar for the WRT)...