Hope you luck gets better. I hope your insurance company goes after her. Did you have the police show up? I mean who plows into a parked car unless they are high or drunk?
I'm not saying get a sworn statement from the kid, but get the kid's testimony written down and signed by an adult witness that the kid said she was texting...
Dealing with getting rear ended by someone WITH insurance take my advice and get a lawyer. This shit is just ridiculous anymore. You have to be the asshole with a lawyer to get anything accomplished. Save yourself the hassle down the road and lawyer up now