You and your SOB are welcome! (Some Other Brand).
The first thing to do is make absolutely sure that you've go the leak stopped. Then you can repair the piece you've cutout. The biggest thing to be aware of is that most adhesives are going to melt that styrofoam into nothing, so you'll need to find something that won't hurt the styrofoam. Good old Elmers white glue might be your best bet.
Not trying to run you off, but you may get more specialized help at the Jayco Hybrid Owners Forum