Hmm...a wireless router...is your wireless network encrypted? You might have some neighbor(s) stealing your precious bandwidth. Granted, encryption can be broken, but some forms are better than others.

Do you know how to get into your router's setup utility? Check portforward.com if you don't know how to get into the setup utility (it's probably going to be something like http://192.168.1.1 if your router is like the ones I've dealt with). I am going to recommend WPA encryption, since it is supposed to be harder to crack than WEP encryption (although we're only using WEP at my house--I want to switch, but my father objects to it for some dumb reason--should probably switch to WPA while he's still gone ).