Hi Sue,
I'm enjoying reading your updates - I got back from travelling a few months ago and I really miss it! About Australia - I'd highly recommend heading west from Darwin. The west coast is far less touristy and just as beautiful as the east. At the very least, I'd suggest a trip to Kununurra which is just inside the WA border. Stay at the Kununurra Adventure Backpackers (tel 8 9169 1998) - they are so lovely there - they seem to make a point of knowing everyone's name. From there, you can visit the Bungle Bungles or go on a canoe safari in crocodile infested waters! Honestly, it was one of the highlights of my trip. If you do end up there, please say hello to the tour guide Darren for me!
Carry on enjoying yourself and take care.