If you don't want to take the risk of not being allocated OAA or just don't fancy not knowing where you might end up you may want to try Jim at www.seacity.com.au.
Back in 2005 we stayed at one of his Glenelg cottages and it was very nice and not too expensive.
When we arrive in January we will be staying in one of his budget properties at Croydon Park, not far from the city. We thought this would be a good base for our first few weeks.

Hope this helps

Dette