I can't promise this will help but I can tell you it was the solution for me, I do however have the WNR834Bv2 router.
My lan setup consists of a win2k fil/print/sql server, two boxes in my kids room(wireless), two pcs in my bedroom(wired), and one old laptop in the living room(wireless).
Out of the blue one day the lan connectivity on the wireless machines became incredibly slow and in some cases died completely. Rebooting would sometimes get a re-connect, sometimes not.
The wired machines were completely fine however.
After much research, the first solution *appeared* to be a master browser issue.
Basically you turn off the computer browser service on all machines which are not designated the master browser. Research master browser for more detailed information.
I saw an immediate increase in network speed after applying this change to all machines, but not soon after, connection/speed problems returned.
In retrospect, I believe this happened because as part of my attempt at fixing the problem as a whole, I upgraded my firmware for the router to the latest version:
http://kbserver.netgear.com/products/wnr834bv2.asp#
I say this, because once I decided to revert the firmware to the version it came with as a test, my connection and speed problems completely disappeared, and I have had no problems since.