Many state DMV's offer a means to obtain a driver's history following an accident, but if they don't have the current address that's not going to get you a current address. The IRS will not give out information about taxpayers. You can try online or professional skip tracing services; I can't promise what results you'll get.
Has his insurance company refused to pay your claim? Your own insurance company isn't going to handle this for you? Or are we talking about an amount less than your deductible?

