Victa,
Your Aussie CPL will get you a US CPL with Private privileges. That is “Not for Hire of reward”. Your instrument rating is not transferred and you will have to do a foreign pilot conversion exam of 50 questions selected at random from their IF database. Then a flight test similar to an IF renewal in Aus. Another way to do it is to do the theory for a US ATP, 3 days and a flight test which gives you the ATP and IF.