USB Wireless Adapter Connectivity Issues

I need a solution to the following scenario:
I have a PC w/Win XP as the OS. For ISP purposes, I was using a Verizon FIOS Wireless Router. All of this is located in my family room (1st Floor). When I purchased my I-MAC, the plan was to place it where the PC is, and place the PC in my daughter’s room (2nd Floor), where I would use a Belkin Wireless Adapter to pick up my internet connection via my wireless router. Well, I have a connection, but it is not coming from my wireless router. Instead, I get a message stating that I have no wireless networks. Please advise. Thanks.