If it were me and I was after planetary images, I would go back to a big goto/ tracking dob. (as big as you can afford and can handle).
I would also get a 5x televue powermate or similar (increase image scale).
after that consider a ZWO 120mm (mono and filter wheels) imaging camera.
you of course will be over budget but if you can stagger then that is a bonus. potentially you could start with a non goto dob and upgrade it to goto (through an upgrade kit) later on.
edit: if you are heading into NSW this could save you some money
http://www.iceinspace.com.au/forum/s...d.php?t=134452