Well I can't give you a definitive answer, however, your routers firmware is extremely out of date. I had some disconnection issues with the same router. Updating the firmware sorted out for me.

They are up to version 4.01.28 for UK and 4.01.27 for outside North America and UK and 4.03.04 for North America:

http://kbserver.netgear.com/products/DG834Gv3.asp