Need a houseguest out!

I decided in mid May to help out a friend who was thrown out of the house she was living in with someone else. Her and her daughter came here with myself, huband and our 3 kids. She had told us it was to be for a short time. She wanted to pay only 100 a month paid nothing when she came. In June we told her that wasnt enough and she agreed to 150 every 2 weeks, she eats our food uses our cable and internet, showers ect. The house bills are 1800$ we thought it fair to divide it by 4 she would pay ¼ she refuses. We asked her to leave…demanded she leave and even put it in writing that she needs to go, now she wont even pay the 150 we got her to agree to. She has no keys to the house, no mail coming here and her daughter goes to school in another district. We live in GA. there was no written agreement as to how long she could stay can we just consider her a houseguest and put her out or do we have to go thru the eviction process? We are renting the house ourselves and just tried to do a good deed. Please help.