You should borrow a wheel clamp. Clamp her new car and demand the money back or the clamp stays on. This girl is taking you for a mug mate. I've had a similar experience with a person I was giving lifts to work for months. All I asked was some fuel money as his place is out of the way for me. I drew the line and demanded the money or no lifts. Got some of it back but not all. Unfortunately people can wear different faces when the subject of money comes up and the "Call yourself a friend" types pretty much tells you where they are coming from. A true friend will never pressure you for money. One of life's lessons unfortunatley. Too bad you have to find out the hard way. Good luck with getting some of it back.