Holy crap Mel, lucky you caught them in the act or you'd be forced to share public transport with some of Brisbane's fine citizens.
Unfortunately it sounds like your car is pretty undriveable, but at least you deprived the scum of at least one more stolen vehicle. They are selfish, lifeless pricks - they steal for profit, to feed an addiction, or because they want what you have. Either that or they were planning on committing further crimes with your car (ram-raiding, joyriding, carjacking etc). They are also among the reasons insurance premiums are so high.
I know it's perfect-world stuff but DAMN I hope the cops find these bastards and put them away.
Best of luck, and let us know if we can help with anything I can probably hook you up with a good price on a pager alarm or something if you're interested??