i have a wireless modem upstairs..and have a desktop downstairs with a wireless card but signall is not strong enough in that room to connect...is there a way to connect another router to desktop to better pickup the signal
If the existing router supports WDS and you buy a similar model with WDS from the same brand you may be able to link the two routers by wireless in order to boost the signal to your wireless adapter. Without WDS you have to link the two routers by ethernet cable as per this: http://kb.netgear.com/app/answers/detail/a_id/1080
Probably simpler to first try to improve your wireless reception.
1) raise the router above furniture level
2) Experiment with channels (some will work better or worse depending on your environment)
3) If you can detect strong neighbouring wifi, use a channel 5 stops away from strongest.
4) Relocate cordless phone base or video sender etc.
5) Be prepared to move the computer (or at least turn it so your body is not between the router signal and the wireless adapter's antenna.