What I said to the GP was "Hey, I need a referral to see this guy. Here's his details".
The GP wrote it up and said "What does he do? And what's it generally about?".
I said "He's a shrink. I have gender issues". That was all that was said. I'd never met the GP before, and I was already full time with legal name change and all that.
I didn't have to go into any details about "the issues". The GP knew I required someone qualified in this matter, and I already had the details of the specialist I wanted to see.
As for pricing - go off what reception says - NOT the website. Call and ask.
I was there in Feb this year, and they said that because I was 1. A gender patient, and 2. Not currently working (I was a full time student), they cut me a very, very cheap price.
You will need to inform them of those two facts when you ask about the current fees. They may still have "special prices", they may not (I am not a current patient, so I'm not up to date. Though I sort of wish I still was... he was cool

).
I know it's hard to out yourself to a receptionist, but they are really nice ladies. You won't have any trouble from them. When I was there they even asked what name and title I preferred (there was no need, I'd legally changed it already - but it was a nice gesture anyway).
I am not going into details about exactly what I paid out, because the fees and policies may have changed, and I'd hate for you to be disappointed (and I don't want anything I say to be used against the guy if he changes his fees later on).
I can't remember if I needed to whip out the healthcare card at all, now I think about it... again - that's something to ask reception.
Let's just say I don't remember having to pay out very much at all

.
Oh, he doesn't drag things out to line his pockets, either. He's actually one of these psychiatrists that uses diagnostic skills (*Shock Horror Probe!*). He took into account the (quite advanced, apparently) status of my transition, personal history, etc.
I know you didn't ask... but here's a few more things I picked up from transitioning in the Hunter that might come in handy.
There's free councilling (they like donations) at ACON's Hunter branch if you're having trouble handling things and need someone to talk to in person (they're in Islington, from memory).
The lady there is called Cath. They deal with a whole lot of GLBT issues - not just trans issues. They can't prescribe HRT or get things moving with the medical side of transition, but she is a someone that can help you in dealing with your family and friends, co-workers, and the like.
When it comes time for your legal name change (if you're going that route), there's a Births, Deaths and Marriages office in Newcastle (though I forget where. It's on the website though).
They accept transition as a valid reason for a name change (even without changing the gender on your birth certificate - 'cause you can't do that until you're post-op) and their comment was "There's more of this than you'd think! We get one of you guys every few days

".
I got in for the "interview" same day without a prior booking - just rocked up with all my documents, waited around for what felt like an eternity, and swiped my card. The interview dude just looked at both my names, looked at me, and immediately went for the approved stamp

.
One thing I never found in Newcastle was a trans support group. It wasn't really high on my priorities list though.
I'd recommend not going to, or relying on "The Gender Center" in Sydney for anything

.
They're well meaning, they're nice, great people that really try to help but DAAAAAAMN they are disorganized and underfunded! They don't even reply to emails!
I went to one of their BBQ's once. The staff were nice, but some of the other people really seemed to have no interest in finishing up transition, integrating, and moving on with their lives. I don't mean that in a "they are happy where they are" way, if you catch my drift.
Aaaaaand that's all I can think of for now. Have fun

.
If you get in to Dr Brash, and he asks how you found him - tell him a nerdy man from the internet named Dante sent 'ya

(Not that he'll remember me without looking up my file or anything... it was a while ago!).