you will need a wired router to do this, wireless are just too unstable and slow. a combo is fine but very expensive. You can get routers for less that 20 dollars.

reply if you need help setting up the router but here is a basic idea:

plug wire into back of computer

plug same wire into port 1 of router

plug wire into back of another computer

plug same wire into port 2 of router

plug wire from internet (if this is a permanent thing) into WAN port of router, it will be the port seperate of the rest.

power on both computers and router

you will want a router that supports 100mbps speeds, and cableing that can transfer that fast too (to avoid bottlenecking)

two really good router companies are Dlink and Linksys, the brand really doesn't matter but these are the most populer and commercially available. you can usually find routers anywhere that sell an abundance of electronics like CompUSA or Circuit City.