First: Are we crazy for thinking we can do this with a 3-month-old?

As some of you may know from facebook, I wanted to go to Supanova (those not in the know: major geek-fest) this past weekend but didn't have the spare cash for two tickets (I couldn't/wouldn't have gone without Scott) so I joked that we may have to travel to Sydney to catch it up there in June. Well! Scott took me seriously, and it may end up happening

We've decided to drive up there, since it's probably cheaper on the whole and we can use the drive as part of our little holiday. But I haven't been to Sydney in 11 years (Paralympics, baby!), I don't remember what stops/tourist sites are essential on the journey. This is where you come in. I need suggestions. What are the must-sees on the trip? What's a waste of time?

How about once we get to Sydney - where's the best place to stay for a couple of nights without breaking the bank? What should we check out/stay away from?

TIA for any help