Get a lawyer.
The insurance company is not obligated to disclose that information to you. You are not its insured (the driver covered by the insurance) and thus the insurance company does not have any legal obligation to give you any details about the policy the other driver had. You may assume, however, that the policy limits are at least the state required minimum coverage amounts. The negligent driver is the one that is liable to you for your damages suffered in the accident. If you sue the other driver you'll be able to compel the other driver to divulge the policy limits during the course of discovery.
After reading all the comments and your problem I think you should get a lawyer.