A couple things. First, the signal needs to go from the wall into your cable box, and then from the cable box into your Slingbox. You can find the details about hooking up your Slingbox in the quick start guide that came with it. Here is a link to that (this is for the Slingbox PRO-HD, which according to your account, is the one you have):
Second, it sounds like you got a different internet provider than what you had before. If that's the case, you'll need to reset your Slingbox to its factory settings, and get it set back up under the new network. Take a look at this article for information on resetting the Slingbox:
Hope you found all this helpful!