I think Christina M has given you a good road map to follow. There are agencies that will help you get on your feet. Get into school. There are so many programs for adult students. It takes a lot of leg work and paper work, but I went to school, had free rent, utilities, phone, etc I also recieved grants and had all my school paid for. Now I make more money and pay more taxes, so, I don't feel a bit bad about taking the help. You can't beat healthcare for pay and job stability. I have a friend that is making over 100k her 2nd year out of school as an RN! You can make more than your daycare bill! Go to a small community college. They have programs geared to help adult students be successful. For instance they offer help with child care and let you check your books, calculators, etc out of the library. Some have family housing available that would give you an apratment to live in while you're in school.
Here's a step I would add. My mom taught me this one. Write yourself a letter. Tell yourself all the reasons you are leaving this man. Put down the good and the bad. How he makes you feel. Your worries for how it will affect the kids. List his many faults and the ways you've tried to work it out. Keep that letter for the dark, lonely times when you are tempted to take him back. You wouldn't have married him and had 5 kids with him if he didn't have a few outstanding qualities. It's easy to gloss over the bad and emphasize the good when you get tired and overwhelmed and lonely. When he comes begging and making promises, pull that letter out and remind yourself of the sober decision you made to give your kids a better life.
Here are a few things to google
Child Care Management Service - CCMS
Section 8 Housing
HUD
Link up America for phone
LIHEAP for utility assisstance
Check with the county you decide to live in. They get block grants for housing, and utilities, child care, and education assisstance.
FAFSA for tuition assisstance