people may tell you you need a router to share your internet connection between two pcs - you don't. Buy two wireless network cards and follow the installation instructions. To share the web connection you need to enable ICS (internet connection sharing) on the host computer (the one that's connected to the web). Don't worry about this just follow the steps in this Microsoft article click here and it will all become clear.
You only need a router if you plan to connect more pc's or don't like the fact that the host pc needs to be on to use the web on the other pc.