Additional Considerations
My first impression of your local network may be incorrect. It was my assumption that you are running the DSL modem and WRV54g router back-to-back. In this configuration, the modem is wired to the router, and the router distributes the internet connection to all local computers.
HOWEVER, “fancy” DSL modems are integrated with a wireless router. This permits the WRV54g router to be used as an Access Point. Does this explain the GeekSquad involvement? If we go this route, then it is a matter to precisely spell the SSID, use the matching channel, use the matching encryption; and configure the WRV54G as a “bridge”. Further down the list of settings comes mode, usually mixed or both.
Your wireless laptop can identify the SSIDs being broadcast in your neighborhood. If I recall correctly, AT&T does not choose an obvious SSID.