There are usually "pre-apprenticeship courses" provided for people who are interested in a certain field of work and want to get their foot in. This may give you some basic knowledge to get an understanding of mechanics.
try these websites (well the one that is relevant to your state). They all have links to the courses provided and a little spiel about what's taught in each one.
https://www.tafensw.edu.au/
http://www.tafe.tas.edu.au/
http://www.tafe.sa.edu.au/
http://www.tafe.wa.edu.au/Pages/Default.aspx
Good on you for taking it on your own back to learn about cars, something you are obviously interested in, as opposed to the majority who go in blindly, post silly things on forums and look like twats.
edit: Because I like your attitude so much, I did a quick search and found this list of courses for a "motor mechanic" link