As Chuck says, it won't work unless you have those details, although there are ways to extract the info from your current router if you look around various forums (it's probably not advisable to mention how to do it here).
But please note Sky actually say in their T&Cs that using a router other than the supplied one is against their terms and conditions, and they could cut you off, so it's at your own risk if you do.
If there's a specific reason you need a new one, contact Sky and explain - they may give you a better one free.