I also say contact DV immediately. There are many attorneys that do pro bono work and they may be able to guide you to one.
As far as your living situation, you are still his wife until the papers are signed. He can't just put you and your kids on the street. Cutting utilities off is a big no no as is canceling health insurance.
I would contact the appropriate state offices for help - there is much out there that might surprise you. DV can also guide you through that. In my state insurance would be provided for the kids as well as other things. There is also a fund to assist families in locating and paying for shelter.
How long have you been married?