regarding an account with allied interstate

I received a letter in the mail stating that I owe $528.73 because of an accident I was in back in the summer of 2007. The vehicle I hit was a Pen Waste Garbage truck. The driver claimed chest pains and went to the hospital for MRI's. He came out with not even a bruise. When I attended the court hearing his boss told me that he was fired because he was a bull-crapper. I am now being fined the above amount for the drivers hospital bills. I was insured and the insurance company is called Able Insurance located on 127 West Ave. Lockport, NY 14094 at the time. There number is (716)434-2026. I do not know why I am receiving the bill and not them. It also states in the letter that "Your payment is due within 10 days for your account with American Zurich Insurance Company. Failure to remit the proper amount by the due date could result in further action". The letter was not sent out until January 8, 2008 and then was post dated for January 11, 2008. Today is January 18, 2008 and I did not receive the letter until this after noon. I am in my senior year at high school right now and I am not sure of what actions I should be taking right now, could you please get back to me as soon as possible with a response. It is greatly appreciated. Thank you for your time.

Sincerely,
Leah