It won't be 127.0.0.1. That's the localhost address (ie your computer).
If it's a Linksys router, I can't remember, but I think that the address is 192.168.1.1. There won't be a username, and the password is admin123.
If it's not a Linksys router, post back with the brand (D-Link, Netgear, etc.), and exact model, and somebody should be able to look it up for you.