Just need some help regarding setting up a shared internet access network at my place, I don't know much about this stuff. We have 2 macbooks and a PC. I'm planning on getting an Airport Express for upstairs (connected to the cable modem) and another one for downstairs which will be a range expander. The PC is downstairs, can I get any old wireless-G network card and it will work fine with the airport express? Cheers!