We’re so sorry to hear about the damage!
The easiest course of action is to contact the person who hit you and get their insurance information. If you don’t have their contact information, you’re not totally out of luck.
You likely filed a police report after you were sideswiped, so you can call the police with the incident report information and the driver’s license plate number. If that person is insured, they may be able to help you. You could also contact the DMV and provide the same information.
If you still cannot find out about the third-party’s insurance, reach out to your own insurance agency. They should be able to help.