What's your router brand? Typically what you have to do to get to the router admin page is connect to it via HTTP. Usually it's 192.168.0.0 or 192.168.1.0... unless someone's changed it (as I have). If that's the case, you can usually figure out the router address from your own IP (assuming DHCP).
Failing that, you can always reset the router to the default settings...
