Hi Andreacdgd,
Welcome to the forum.
Have you checked out the sticky posts at the top of the forum? The "Please read" and the "Thinking of emigrating" have a lot of info to help you including links to schools.
If you search through the threads (top row with black background - 3rd from the right) you'll find recommendations for agents and their approximate costs at the time people used them. First consultations are usually free, and you want an agent that is registered with MIA and/or MARA (see "Please read" post). There are 2 agents who are sometimes on this forum - Alan Collett and Liana Allan. They are based in Australia but I think that Alan also has offices in the UK.
Before you start checking into schools you want to make sure that you can get visas to come into Australia. It can be harder than some people assume so you need to start there really.
I'm based in South Australia although I'm about 400kms south east of Adelaide. So if you have any questions about the state ask away and I'll answer your questions (or point you in the right direction
).
Regards,
Karen