WYNNUM:
The point here is you can not fly a US aircraft with an Australian License. You must have an FAA License. (I think you can covert your Australian license call the FAA) You can fly a VH- registered aircraft if you can find one in the US or of cause you could take one to the USA via ship/ferry flight. Remember also you need a Australian LAME to do the work on the VH- Aircraft in the US as well.