Hi Cristie,
just do this:
1: Get a wireless *router* and plug Your Internet connection + cable-connected computer into it..
2: Get a wireless *network card/plug* for the computer You want to be wireless.
There is a slightly cheaper solution, but that would get more complex..
and this isn't such an expensive solution, probably max. $200 for You.
You'll also have the advantage of easily being able to connect more computers
by just adding a wireless card/plug to them as well
