Welcome
I think you should get a router. I've got a Linksys one from PC World for £50 including the wireless USB bit. Anyways, It's caused me no problems. I can share files/internet everything over it. If you computer is close to other one, I sugest you can get a wired cable for the router, that means, you'll get a better connection and stuff. I've got it for my laptop and it's very good.
Hope you can find something soon!