Luis,
The Sports Aircraft Association of Australia is having its annual convention (fly-in) in Cowra in NSW during that week. See:
http://www.saaa.com/EToC/main.php
The convention holds little to many US fly-in events but it will have a good representation of RVs and many other interesting aircraft. Friday and Saturday are usually the best days. It would be well worth the trip.
Now Cowra is not a short drive from Sydney but you might be able to entice someone to give you a ride to Cowra if you can squeeze it into your schedule by checking into the RVs_in_Aus Yahoo group and asking the question.
I have not attended for several years so I am unfamiliar with what is available - I believe limited motel/hotel accommodation is available.
Doug