The Netopia router doesn't support repeating:
http://www.netopia.com/support/hardware/technotes/NIR_100.html
You will not be able to get the WG602 to repeat to the router - or rather, the 602 may in fact repeat traffic to the router, but nothing will come back. So it won't work.
Once possible option would be to buy a second WG602. This can then be connected directly to the router, and the router's wireless turned off. The 602s can be used to increase your wireless range by repeating.