I don't know too much about Sydney anymore, I moved away about 10 years ago (not far, Newcastle, just 2 hours up the road, but a completely different life

) We'll wait until all the Sydneysiders get on later in the day. I'm sure we can organise a drive and stuff.
It gets pretty hot at that time of year, we often get temps around 40C

So pack your swimmers and sunblock. There are plenty of nice beaches everywhere, Bondi, Coogee, Manly etc in Sydney, but we have nicer, less crowded beaches up here
You can do the Bridge climb, get fantastic views of the harbour, Harbour Cruises, a day in The Rocks or Darling Harbour, a trip out to the Blue Mountains, a trip up to Newcastle
You will fill up 2 weeks easily
Just found this site
http://www.sydney.com.au/
(I don't know how they thought of the web address)