Hi Paul, and welcome in advance.
Check out the relevant threads in the forum for details of track days in the various states. You'll also need a CAMS licence and membership of a CAMS approved club.
The MSCA days in Vic are some of the best organised, and they host events at Sandown, Winton and Phillip Island.
You'll find loads of help on here. I've found the group to be the best, most knowledgeable and most approachable of any marque specific forum I've been part of. If there is an answer, someone here will know it, including sourcing a car (I have heard of people even renting a cliosport from Hertz - just don't leave your helmet in the boot by mistake )
If I can offer any of my limited knowledge or help, feel free to ask.
Good luck and enjoy your stay. Ian