HELP! Need wireless on eMachine t6410

Hi,

I'm in a sticky situation. A) I'm in the middle of a move to a larger house in the country. B.) I'm currently in several computer classes at my university. C) My beloved laptop has finally died a rather dramatic death and now I need to set up my old desktop as my main computer for a little while. Since I generally run Ubuntu and will need a linux distro for my classes, I'll be setting it up to run Ubuntu 10.10.
Before the crash I was going to set up the tower as a simple home server, but since I live in the middle of nowhere, my fastest internet option was the 3G Sprint Hotspot on my and my partner's phones (the server will only work when one of the phones is near, but we'll mainly be using when we're home).
My question is... What hardware should I purchase to get wireless on my eMachine t6410? Internal options are obviously preferred, but I'm not sure how to find exactly what I need. Can anyone help me?