Help please! Where to connect??

HI, I want to make a cantenna but I have some doubts. I have a WLAN Broadcom card. It has two little connectors (one says "main" and the other "aux"). Should I Solder the coaxial cable directly to one of them? If so, which one and how should this cable be properly soldered? Then What about the 2 little cables that come from the computer, should I unplug them? One of them? none???
Is there a risk to spoil the computer in any way (because of impedance or something like that)?

Hope you can help me and I'd really apreciate it.
Thanks a lot.