Get a port scanning tool and install it on your windows computer. I use angry IP scanner (http://download.com.com/3000-2085-10219888.html?tag=lst-0-1) .
Make it scan your network 192.168.1.1 through 192.168.1.254 or 192.168.0.1 through 192.168.1.254
It will show your 'live' IP addresses and your 'dead' IP addresses on your local network. Then, after you've identified which one your router is...you can input it into your web browser and config it.