As mentioned earlier get a router that does both wired (ussually 4 pc's) and wireless.
Also VERY important once you get it up and running go into the router settings and set it up. set a user name and a password for the router then go into the wireless settings set a name for your SSID then set your WEP for atleast some protection.
The SSID is the name you give your router IE. ODBALL'S router
The wep is ussually set at 10 HEX digits you can increase this to 28 I beleive but for just basic home use 10 should be enough. There are more advance settings you can setup if your really worried about hackers like MAC filtering . PM me if you want more info on this.
I tell customers I setup with FIOS that for the most part the regular WEP settings is good enough. IF a hacker REALLY REALLY wants in they will get in but unless you got something they really want they aren't gonna bother with you.
Personally I use the 10 key wep with MAC filtering. This tells the router which PC's are allowed to access it and the net by inputting each pc's MAC address. Anyone else it gives them the digital equivalent of the bird. With only yours and the GF's pc it's pretty easy to setup. Its when like me you have 2 wired desktops, 2 wireless laptops and 4 stb's that pull IP's from the router that it takes an extra 10mins to setup