Well Im in Sydney and I would be happy to meet up with you if you got here. We could go out for a meal one evening.. A Day time catch up would take time out of sight seeing...
There are things to see in Sydney.
There is the harbour bridge, the opera house, the zoo, then there is the blue mountains (the 3 sisters etc), then there is some other amusement parks such the aquaium, the powerhouse museum, the art gallery, centrepoint tower (which you go up to the observation deck to see around sydney as far as the blue mountains)
then you could take an hr and 15 min drive south to Jamberoo - a water recreation park which is fun for all ages
you could go south for a few days and stay at one of the caravan parks on one of the beaches. The south coast is absolutely beautiful.
Im sure you could get a day bus trip (3 hrs one way) from sydney to the capital ACT canberra and do some sight seeing tours such as visit parliament, and the other sites there.