Pay the fine, then sue the car owners for damages

You have to front the fine.  If you don't pay the fine, the county is going to put a lien on your property, and eventually may even sell the lien to investors and go after the title of your property. 

After you pay the fine, you can sue the the car owners for damages in small claim court (if your local small claim is <5000), or have court title the confiscated car to your name and sell it... 

You absolutely have to pay the fine NOW.  You can seek damages in many ways after you pay the fine.  I don't see alternatives.