International Issue Canadian Mom living in USA, daughter in Canada

[GPS_]

I need help with this question. I am a Canadian married to an American, I am in the USA on a CR1 Visa. My kids live in Canada with their Father. Problems have arose and my daughter wants to come and stay with me now in the USA. How long legally can she stay here? If she decides to stay, can we process her paperwork from the USA or would she have to go back? At this point her Father has kicked her out of the house, so her going back is out of the question. What about schooling for her? She's 15. Any help would be appreciated. Thanks