how can I find out who was my auto insurance co from 10 years ago?

To find out the insurance company you had in 1998, I suggest you write to the Pennsylvania Department of Transportation. Provide them with your name, address (at the time), and vehicle make and model. In the letter you should request the name of the insurance company and policy number in force at the time of the accident. You might also request this information from your insurance agent (if you can recall who that is). If a lawsuit was filed, you might be able to obtain the lawyer's name from the civil clerk of courts at the courthouse. If medical records were requested of her physician's, those offices might have a letter from the attorney requesting copies of documents. You might also request a copy of the police report from the investigating police department...the report should contain the name and policy number of the insurance company.
Good luck!