advice on installing wireless adaptor with livebox

I have been with freeserve for years using my own router(netgear). However, my son wants to join Orange and install a wireless adaptor to his desktop to go with livebox. I notice that Orange prefers : Speed Touch wireless adaptor connecting via usb. Can anybody recommend an adaptor which connects to ethernet card alrady in his machine. Also is it possible to connect wirelessly for the first time without first connrcting through ethernet cable.He already put his machine and peripherals upstairs, but the BT socket is downstairs!