Is this the device you are using?
http://www.trendnet.com/products/proddetail.asp?prod=100_TEW-650AP
How (exact device) are you delivering Internet access to the TEW650? The TEW650 uses WDS to route internet traffic through the main router with internet access, so the device on the other end (connected to the internet) should be setup with WDS also, assuming it supports it.
Some useful info on WDS
http://en.wikipedia.org/wiki/Wireless_distribution_system