Hi,
The Australian Bureau of Statistics is a good starting point:
http://www.abs.gov.au/
Most information on the site is free - it just takes a little time to sift through it all.
Other sites such as Ibis World are also handy -
http://www.ibisworld.com.au/ - the information is not cheap, but you might get some useful insight.
Also do some Googling as well - often you will find Universities who have completed research in specific areas which they have made available to the public. (I've used this in the past).
Regards,
Geoffrey.