Gigafast Wireless adapter question

I have an Imac 17 inch 1.25 ghz. I bought a Gigfast usb adapter to go wireless. I installed the driver, and followed the guide instructions. When I go to Network it shows the adapterand the IP and Sub addresses but no router address. It does not give me the Apply Now option. The icon next to the gagafast adapter in network is yellow. Not sure what I need to do to get it to connect to my linksys router. Someone mentioned changing to WAP. Currently my router is set to disable. I have two WPA options: wpa radius or wpa pre shared key....