AP in client mode problems

[Bryan Irvine]

I have 2 Linksys wap 54Gs.  One is in AP mode and allows for wireless
connections, the other is in client mode, and allows my 'wired'
machines access to the network.  Problem is that the access really
really sucks in the garage.

I have a good signal, at least so says macstumbler, the APS are
seperated by about 20 feet, with 2 walls in between them.  My signal
strength to a laptop when in the garage varies but rarely dips below
even 75%.

Another oddity, is that I have 2 computers presently hooked up, and
when one is busy the other one can't access the internet.  For example
if I have an ftp download going, the second computer is utterly
useless.

There are other AP's in my area, but they aren't on all the time, and
it makes no difference if they are.  Both of my AP's are running on
channel 1, and the other AP's are running on 9 and 11.

Ideas on troubleshooting for this?

--Bryan