HELP ME! Niece, 19 yo w/bipolar/depression, living w/me for 8 months-How much is 2 much? What 2 do? Parents r

out of the picture, washed hands of her 9 months ago-just dumped long distance BF to take up w/Satan lover-has no job-no home-nothing of his own who lives/feeds off of others-now in "FLOVE"-while I work-feed her-hold her hand through DR. visits for mental and health issues-help her get into college-help with her bills-and she talks smack, is generally disrespectful to me-spends her money on meals her satanist-purses and getting her nails done-she's called the police on me and now they say she has established residency and I can't kick her out, even though she pays nothing towards food, household expenses, or the money she owes my Mom or me. At what point do I call this quits? I know she is mentally disturbed, but she's been "stabilized" for 4 months and no end to the problems. The fosters who live with me are being dragged into it, with her blaming them for all her troubles. Tonight, she called the police, and I called my Mom who took her in for the night. Cop said she can return