Call her insurance, get an estimate or two. Your car needs to be repaired to the condition it was in the moment before she hit you. You'll most likely need to replace the energy absorbing inserts in the rear bumper at least (that's where the energy from the impact went, not your chassis). Insurance pays for that almost as a matter of course in a rear end accident. The estimate(s) you get will determine if the bumper needs to be replaced. They'll probably try to repair it as long as the cost is less than the price of a new one.
