Do you have any neighbours nearby? Check with your laptop and see if there are any unsecure networks in range; I'm at the edge of a residential area and the last time I checked there were half a dozen networks showing up, most of which were called Lynksys or Dlink, and several of which were unsecured. If you don't have a home network set up, a relatively cheap ethernet crossover cable would let you tether your laptop to your desktop to share the internet connection, or a wireless card or USB wireless adapter are relatively cheap (probably still too expensive for a single usage, though).
