Hi,
Two who get many mentions here, but are in Sydney, and/or Melbourne:
https://www.bintelshop.com.au/welcome.htm
http://www.andrewscom.com.au/site-section-10.htm
There are several others including those advertising at right. There is also the very busy astro trading forum of course right here on IIS.
Welcome to Australia, and to Southern skies!
Cheers