Room mate left, remaining utilities bill?

I had my cousin staying with me as a house mate for 9 months. Those 9 months she only ever paid me $75 a week due to that's all she could afford. She was offered a job and decided to leave and move in somewhere else. Our last electricity bill was $1000+ . In my home there was me, my cousin and my 2 daughters and now I'm left paying the bill. She isnt an easy person to get along nor an understandable person. So how do I ask her to help me pay a little part of this off, or should I ask her? Or do I pay it off myself seems I have 2 kids here as well. When she was here she only paid an extra $50 twice for the bill. Just needing some opinions, thank you.