How can an adult deal with bullying?

It's not like I can run to the teacher, principal or a parent. There is this bad piece of work girl who is making my life miserable. We were friends for a while, but she was using me to keep paying for her tab, if we went shopping she'd be sneaky and get me to pay for her purchases, same with dinners and then the last straw was an expensive trip so I put an end to the relationship. She has since spread rumors about me and is intimidating for me to be around to the point I have stopped going to church because she goes there too and is popular with lots of friends who are all now mean to me. I went last week and left right after service without staying for the lunch and talking to other members because of the discomfort she makes me feel and I don't want to switch congregations - the other one is very far with a small older crowd I don't feel as joyous going to. I don't go anywhere where I think she will be at and that is making me miserable because we live in a small town and it has cut off my social life. Please help with any advice. I am hurting a lot. Like one of the last times I went to church her and her friends sat in the row right behind me and were saying a lot of rude things about me but I didn't respond because we're not on talking terms and I was very outnumbered. Everyone seems to like her which makes things so much more harder and painful and difficult.