I found the latest official firmware release for my WNR3500Lv2 at this location on the netgear site:
http://kb.netgear.com/app/answers/detail/a_id/2649
Just in case anyone else is simply interested in altering the behavior of the stock firmware. This page seems to include source for many of their routers.
Link you have mentioned is for the source codes of the routers. To get stock firmware for your WNR3500Lv2 router you have to visit this link.
Exactly! I should have been more specific.
I have changed the title to reflect that. If you want to change the original firmware, like me, this is what you need.