All the aviation teaching for apprentice AME's is done in Sydney (and NSW) at Padstow TAFE.
I'm not sure if they do pre apprenticeship courses but these courses do exist and they will know where to find them.
I suggest you get on to Qantas and submit a resume. They are the largest hirers of apprentices in Sydney. Find out when their next intake of apprentices is and keep hassling them.
Buy the Australian newspaper on Fridays as they have an aviation section with jobs(although rare to see any for apprentices). It should keep you up to date with industry news which will hold you in good stead in an interview.
General aviation is pretty dead. Jobs are hard to come by and pay is poor.Stick with the airlines.
Give someone from Padstow TAFE a call. Maybe they have a careers adviser who can steer you in the right direction.
Good luck