I had my HSV fully 2-packed and flow-coated by a place called UNIQUE SPRAYPAINTING, in Arndell Park (back of Blacktown). They did a fantastic job for me and three friends who i also recommended them to. They have some pretty big contracts like Arnotts' fleet of cars and trucks and have done many show cars some of which have been featured in Street Machine and have Summernats trophies.
I'm sure there are plenty of great panel shops out there, this is just one i know and can recommend.
I would ball-park a 2-pack respray with minimal prep work at around 5-7grand. But as MJ said, people have paid massive amounts too. The way i see it is it doesn't matter how much you pay someone, if they are an average painter it won't make a difference. (I prepared my vette and contracted two well respected painters to hire a downdraught booth and apply the colour for $2500 and have seen $15,000 jobs that aren't as good) Then again a first class painter may charge more for their skill...and with 2-pack you want it done right straight off the gun!