From the sound of your question, you don’t have collision coverage. First, you need the information on the car that hit yours. The insurance could be directly through the rental company, or the driver might have their own policy that covers them while driving the rental. Hopefully, you took down the name, address, phone number and insurance information on the person that damaged your car. If you didn’t, let’s hope the police did. Get a copy of the police report from the police station and see who the insurance company was so you know who to contact for a claim. If you don’t have any of this information and you don’t have collision, you are out of luck.