I was having the same problems with that card on my ipaq 1945. Did a lot of searching and found many threads about it on the Socket forum. It seems that almost EVERYONE is having problems with this card due to lousy drivers. I have the same router as you and have it set on channel 10, as others on the Socket forums reported having some luck connecting on channels 8-11.
I have recently started using
Boingo http://www.boingo.com/download.html and have been able to connect consistently.
Hope this helps, and good luck!
Marshall