Hi Peter
First up - welcome to IIS - you will learn a lot from the people here (as I have!).
Ryan's advice about the HEQ5 Pro as a starting mount is spot on. Many would consider this to be the starting point for a mount capable of taking long exposures. I have one of these mounts and SW120ED Back Diamond scope to go with it. Coupled with an Orion ST80 guide scope I have successfully been able to take 600" subs (light frames) on various DSOs without having the scope set up permanently in an observatory.
Before buying anything though could I recommend to you that you attend an astro camp or two and have a look at what other amateur astronomers are using and why they use the gear they do to image what they do. In SA you have:
https://www.assa.org.au/
Although it's a bit of a lengthy travel, you have the Snake Valley Astro Camp coming up here in Vic in two weeks (
http://www.iceinspace.com.au/forum/s...d.php?t=174084) and I believe that the VIC South Star Party run by the ASV is also on that weekend. So as much as you may want to get started - refrain, research and save for quality gear that will help you achieve want you want.
Hopefully this info will be of use to you.
Kind regards.
Paul