This site seems to give you a bit of a guide
Home Mortgages Australia - Mortgage Australia Dont forget to take out legal fees, stamp duties etc in your calculations as well - stamp duty can mount up. BTW interest rates have gone up a couple of times since that table was designed so bear that in mind.
You may also be entitled to a first home owners grant if you have not owned property in Aus before but I dont know what the regulations are for that.