Hey Ryan..
When I applied for Cabin Crew I waited around 1 month, however I have heard of people waiting for ages.. What I suggest you do is keep on sending the application through on staff cv every month. By doing so at least you know they are constantly looking at it. Also possibly send them an email and tell them you are anxiously waiting and have never been interviewed by them before. On the day I attended one guy called them 4 days before the Melbourne interviews and asked if he could come along, they allowed him to do so and he got through...
Goodluck with that, I've had my medical with them last week for Guest Services and now waiting by the phone, fingers crossed
.....
Cheers
SocialFlyer