Totally agree with the suggestion of the Heysen Trail as a long trail closer to home. It is accessible by bus at a number of points, so you could do a number of weekend trips as point-to-points.
I'd suggest a couple of weekenders before working up to longer 5-7 day trips. Perhaps the 1st couple of trips are car-camping day hikes, so you can bug out if things go disasterously wrong.
You're really looking to learn in 3 key areas:
* gear selection
* menu planning (keeping lightweight and non-perishable meals appetising for 6 weeks while your nutritional requirements go through the roof can be a challenge)
The Flinders Ranges in winter is a good opportunity to test your sleep system (sleeping mat, bag, clothes) in lower temperatures.
If you are building up your kit completely from scratch, then you are probably looking at $1200-2000, but it should give you many years service. In terms of reducing that cost, take a look at the market square here for some 2nd hand items, keep a look out for sales at outdoor shops (and at Aldi?), do your research before you buy (so you only have to buy once) and ask questions on these forums about specific proposed purchases. Placing caches involves about 1000-1200 km of driving, plus getting across from Adelaide. Food for 5-6 weeks is an expense, but ya gotta eat anyway, so it is really an issue of buying groceries up front. Some miscellaneous expenses at Thredbo and Hotham (a night's accomodation at the YHA for a hot shower and soft bed, some fresh food and a cold beer, etc).
Chapman's guidebook is probably the best starting point for AAWT planning and preparation, so that should be one of your very first purchases.
Fitness is another thing that will make your trip easier and more enjoyable, but with 10 months to play with, there is plenty of time to work up to it. Trail running in particular is excellent preparation - fitness, keeping balance in rough terrain and navigation, without being a huge time suck (as a uni student, you've still gotta pay attention to your studies in the meantime).