To answer your question on how to reconfigure the Slingbox to the new router, the first step is to reset your Slingbox back to factory settings. Here is a link with on instructions on how to do just that:
Once you have performed the factory reset, you will need to setup the Slingbox just like you did initially on Newwatch.Slingbox.com on a PC or Mac.
Hope this helps!
Sling Media Forum Moderation Team