While you are having a frustrating run with your car I would suggest you give it more time. It is still under warranty so any repairs it might need are covered. We don’t have lemon laws in Australia, like they do in other countries, and that makes it hard to get rid of troublesome cars. If you want to pursue it consult your state government consumer affairs people, and perhaps get legal advice.
Under the Australian Consumer Law introduced in January 2011, a consumer can request a refund or a replacement for persistent problems if the car doesn’t do the job it’s supposed to do.