I think it is a terrible idea, frankly.
Remember, the AO is the best attended tennis event on earth, every court is packed, even out on court 22 at 10 am (ok, so Rafa was practicing, but still
However, if you MUST, here are a couple of things you might be able to do to make it bearable fro all concerned.
1. forget about taking her to Rod Laver. People will hate you.
2. the outside courts are actually pretty accessible via stroller, if you get there nice and early you can find a good spot and enjoy the day. There is shade and grassy areas nearby
(down behind showcourt three especially)
3. The 'tag-team' idea for the night matches is a pretty good one. The area with the tables and the fountains etc right outside Rod Laver is good for kids as it's nowhere near any of the courts and has plenty of space. (and a big screen)
4 The showcourts (including Margaret Court) are usually PACKED, and once you leave you won't be able to get back in fro a while, usually, so forget those as well.
in short, terrible idea, but you can probably manage a good time by haunting the outside courts (where you see some great matches and can be right up close to the big guns practicing quite easily) and keeping your child out of teh arenas
(Melbourne has some excellent commercial child minding/stroke nanny services, just saying..)