I'm so sorry and glad your family is ok!!! I know you must be in shock but you need to report the accident if you havent already and find a personal attorney. Hopefully both insurances will compensate you. Your insurance can provide you with a rental too.
We had a car rear end us 2 years ago. 4 cars involved. I ended up in the emergency. Our car was totalled. We sued and got compensated for my injuries and for the car. I hope its not going to be stressful for you and things get
taken care of quickly!