Hi Medo!
Really meant to reply sooner. This is one of my favorite topics! I do have to admit that I am really unfamiliar with Australia's growing conditions. I'd imagine though that you can find something similiar to our USDA Plant Hardiness Zone Map. An example of it is here...
http://www.usna.usda.gov/Hardzone/
This should give you a starting point as far as determining planting dates and the varieties of plants that will grow in your area.
Another suggestion would be to get a calendar and label it your gardening calendar. This may seem like alot of work, but will come in real handy in the years to come. You also can easily count backwards from your lfd (last frost date) to begin starting seeds. I would suggest that you try both starting some of the simple seeds and using transplants from your local nursery.
Your local nursery will be a big information place, once you can find one with knowledgeable people that you can trust.
What are your goals? Do you want to grow veges, cut flowers, exotics, perennials, fruits, container gardening, herbs etc....
Next, get a good google search for catalogues that you can drool over.
Then think about starting a compost pile.
If you are planning on doing a raised garden, be sure to take the proper steps in planning and soil prep. Some things can't be rushed, but there are always things you can do too. Meaning, you can purchase a dump truck of "good garden soil", or just a few bags for your garden.
How big do you plan on starting and what do you want to start with.
The seasons play the biggest role in determining what you can grow.
I completed the master gardening program in Texas a decade ago and also have a small horticultural business here in LA with 30x100 and 18x24' greenhouses in my yard. I specalize in gourmet peppers and sell them wholesale.
I'd be glad to help in any questions you may have. I do know that Australia has some really unique native plants and some pretty darn good horticultural programs.
Also remember that gardening can be expensive or cheap. But be prepared for an initial investment to get going.
Good Luck!!!! Hope to hear how it's going!!!!!!