How to get extra work on the Gold Coast?

Hi I am looking to work as an extra for tv or film but i have no idea how to go about it as i joined a couple of agencies in the past and they never got me any work. I don't have any experience and that's why i want to start out as an extra....i'm 28 which might be a little old for starting out but i've been interested in acting all my life. I've also looked at doing course but i can't find any courses on the gold coast that are for Adults, they all seem to be for children and teenagers. Well any advice regarding getting work as an extra and about courses in my area would be greatly appreciated!