Loose Rear Bumper

I was hit backing out of a parking lot on the right side of my rear bumper. The person that hit me didn't bother to give me his insurance information (if he had any), so I'm not sure what to do about the bumper.
Anyway, while it's staying on just fine, the right side of the bumper has cracked away from the metal of the car, and under the trunk hood, these (plastic?) pegs are all loose. Obviously, I don't know much about car repair... but if possible, is there a way to fix the bumper well enough so its not endanger of breaking off? At least for a temporary fix, since I don't have the time/money right now for body repairs.

Thanks alot,
Mary