Hi Kee-Yang,
Welcome to IIS.
This article from a major australian newspaper might give you a few ideas:
http://www.theage.com.au/travel/road...0311-8upf.html
as a tourist, I'd think about giving Zane Hammond at Magellan Observatory a ring. He has self-contained farm-house accomodation available for rent at reasonable rates, lots of 'scopes and expertise and is only about a 2.5 hr drive south-southwest of Sydney.
Maybe even think about Mudgee Observatory about 4 hrs northwest of Sydney:
http://www.mudgeeobservatory.com.au/index.html
they don't have accomodation for tourists but you can stay in the town of Mudgee 20mins drive away (several motels there) and the facilities on the property are good.
Hope you have a great trip to Australia!
Best,
Les D