You can post a position wanted on our HFI Connect jobs group. You could also do the same in CUA Central - as a CUA you can join. You might be able to network with some people there. Why not put a post in the forum there. Best of luck.
we don't deal much with product usability but specialise more on usability online so you will most likely be better off contacting companies that focus more on product usability testing as you mentioned that is what you want to get in to more. Plus we are not based in Queensland where you are after an internship but actually New South Wales.