This is my trip itinerary to Australia, what do you think?

I’ll be in Australia for 11 days and I already built an itinerary. Since I have two extra days I’m not contemplating I would like to get some opinions where else should I spend them, should be near any of the places I already have. I’ve never been in Australia so, do you think I’m visiting the right places or would you suggest different.

ITINERARY:

Sydney (2days) – Blue Mountain (1 day) – Wollongong (1 day) -Melbourne (2 days) – Great Ocean Road (from Torquay to Allansford) (2 days) – Mount Gambier (1 day)