My last several posts have been primers on attic and roof insulation. You might want to click through some of the links.

There are many large roofing outfits that will do roof work in the winter. I used Superior Roofing (Littleton MA. I think) last year. Got their name via Angie's list. If you are willing to pay, you don't have to wait for spring. The key words to get their attention are "I have an ACTIVE leak."