Looking on the web, that computer uses a broadcom device rather than an atheros device. You need to use the b43 kernel driver (which you have), and you also need to cut the firmware, which the b43 driver needs.
This forum has instructions in installing the firmware. It is for Fedora, but you want the same firmware from the wrt site:
The device needs to be working before you can configure your wireless device. If you have the wireless-tools package installed you can run "sudo /usr/sbin/iwlist scan" to see if the device detects access points. If it does, you can proceed to configure the device, authentication & your network settings.