Thanks for all your suggestions :) I've just booked us into Oaks on Lonsdale as I got a good deal, and we will be over the other side of the city on the nights we're staying in DH's 'work' hotel.
Feeb - that's a great list! Is monkey mania a playcentre? No car, we're just going to go for public transport.
Junglemum - I'll have to take the stroller - DD got so grumpy the last couple of times I put her in the ergo, I don't want to risk it being my only option the whole time we're there. But I am quite experienced in pushing stroller/pulling case as more often than not DD and i fly and meet DH places etc, so I'm not too worried about it. I'm going to give the majority of our stuff to DH to take the day before anyway ;)
PZ - we went to the Australian Museum a couple of weeks ago and DD quite liked the dinosaurs so that could be a good one too
ETA - just in case anyone else is using this for their info - I just looked on the skybus website and they have mini buses that link to your hotel included in the price :)