I think I'll install a hidden dog chip kinda thing (get a dog, get it microchiped, rip chip out of dog's skull maybe?) deep inside my car and if it gets hijacked just look up the location, rent a taxi, shoot everyone there and get my car back.
Foolproof plan!
But that must suck.
Call the cops and give them your licence plate or something, that could help (have them look for a car with the same licence plate).