With the housing market as it is we are forced into validating in december so we have booked the flights and go on the 5th dec for 5 weeks, me the other half and 2 boys aged 3 and 6. 1 1/2 weeks in wollengong 2 weeks in caoundra and the rest back in wollengong. Any advice must see attractions in any of our destinations.

If you are staying in Woollongong, it's an easy 45 mins on the train into Sydney. Then you can do the usual touristy things like Harbour Bridge (although your kids are too young to do the actual climb. Might be able to just climb the tower though: need to check that), Opera House, Taronga Zoo (worthwhile), beaches etc. From Woollongong you can also drive into the Blue Mountains (takes just over an hour to drive).
While you are staying in Caloundra, although I've not been there, I think it's not that far from Brisbane so you can get into the city easily enough. Also go to Australia Zoo (Steve Irwin's zoo in Beerwah, good day out), beaches around Mooloolaba are stunning. Also driving from Caloundra to the Gold Coast theme parks would probably take around 2 hours to drive.

P.S. Just found info on the Harbour Bridge. To climb the pylon costs $8.50 for adults and it's free for your kids as they are under 7 years old. Go to www.pylonlookout.com.au