If you've got twin time and instrument time, give Australian Helicopters a call. THey're currently looking for a Bell412 HEMS captain at their Warrnambool base (about 3 hours drive west of Melbourne). Obviously you'd have to live there.
Google them and contact them at the Brisbane head office.
Otherwise Melbourne is a bit of a dead end for helicopter jobs unless you want to work for smaller operators that generally don't pay too well.