Do i give her an ultimatum?

I have a friend who is also my second cousin who is going through a nasty divorce with ugly custody issues.I invited her to come stay with me almost 6 months ago for moral support ,and till she could find a job to get her life together.However more and more of the negative things that her soon ex.husband has said about her seem to be true?I asked that she give me a 100 dollars a week in rent after she found a job that she always seems to forget about paying. I got her a job as a secretary at the school i teach at and she is on the verge of being let go to put it kindly!because its her first job ever and she is being plain lazy.I watch her daughter who is 2 yrs older than my daughter and her son so childcare is not an issue for her.She cant afford rent or food but she still finds a way to buy expensive bags, clothing ect.?I caught her shop lifting while out shopping with me ,she is partying, and i believe she is abusing pain killers.I want to help her but dont know how?