How can I get internet through my wireless laptop to my desktop?

Okay I have a desktop that I need to place downstairs. My desktop normally uses two RJ-45 cables to run in full duplex. My wireless PCI card will not install on vista 64-bit. But I have a laptop that has built in wireless. I'm wondering if it is possible if I could plug my desktop into a wireless laptop to get internet through it. My desktop has Vista 64-bit and laptop has XP 32-bit. (Please don't post dumb answers about stuff you don't know if your just trying to get points.) Please answer if you actually know what you are talking about or know some kind of thing to go to or possibly a link that's relative. Thank you.