you havent tried everywhere
Join the Royal Aeronautical Society - despite being a predmoinantly UK based group, there is an Australian division. Once you're a member, you can recieve the membership benefits, which include career guidance and help. It is a very good service and should help get you on track as well as giving you heads-up on less advertised positions.
Unfortunately an undergraduate degree in Aeronautical Engineering won't be much use in the physical maintanence side of the industry - its a whole different skill/knowledge set. You're destined for a swivel chair im afraid.