Does this help?
This lists the Schoolies hotspots
Schoolies Location Information (http://www.schoolies.com/2009/about/location-information.asp - broken link)
Anybody NOT on Schoolies that is hanging around Schoolies areas and socializing is called a Toolie. Not something you'd want to be a part of I'm thinking.
Being older and having had the misfortune to book holidays in Schoolies hot spots in the past if you're not wanting to spend your time watching drunk kids trawl up and down the main drag and come back to their apartment besides yours at 4am and continue with their festivities I'd say give any Schoolies hotspot a WIDE BERTH. (although last time my then 12 month old adorable neice did exact some revenge by waking EVERYONE in a 4 mile radius each morning at 6am!
)
The good thing is looking at your dates you might just luck into the early Schoolies festivities where things are a little quieter.
You maybe want to consider doing your beach trip in the first 5 days of your stay or maybe even making it 3 days to enjoy somewhere coastal, remembering that population swells in coastal places on weekends and then spend the rest of your time in the cities where the Schoolies are not.
I personally love The Gold Coast but I'd NEVER stay in Surfer's anyway and always spend my time down the south end of the coast at Currumbin. It is still lovely, close to what I want AND away from the city itself.
Oh and if you're leaning away from Oz, then yes, Queenstown in NZ is just magical and has everything you could possibly want and then some BUT I'm not sure if they have Schoolies or not.