Elective Caesarean Procedure - Sydney Public Hospital

[castle]

Cher, congratulations on your pregnancy, and welcome to Australia if you are new here.
In the public hospital here, you book the hospital after your initial "booking visit" in the clinic (at about 14 weeks), unless you are having a private OB. The hospital booking date is based on your EDD, unless you are told otherwise by the OB or midwife. Don't worry, the hospital just wants to have an approximate idea and get all your details in the computer. If it is agreed at this visit that you should have another caesarean, and I think it will be, then they will tell you which week of your pregnancy to book it for. I'm not sure if the admissions office will give you a specific date at that point or not.
I think that since you've had 2 c/secs already, there will be no difficulty booking an elective 3rd one. You will not be able to choose the date or time. As Marydean said, they will probably do electives only on certain days.
How long you stay depends on your recovery, and unfortunately, on how busy the hospital is at that time. I stayed a week with my last because I had a baby in NICU, but I was told after 5 days that I could go home if I liked. There was no difficulty about my staying. If you are feeling exceptionally well, you could leave after 2-3 days. If you strongly desire leaving early then you can discharge AMA in any case.
Your room will probably be a 4-share which motivates most women to leave asap! If you have private cover, you may be able to stay in a single room. This is what I did. It depends on the hospital--how many single rooms are available--and how they prioritise them. They try to save them for very sick mums, but if there is plenty of space a c/sec mum would probably get one, whether or not she had private cover. With a public hospital, however, there simply aren't any guarantees.
HTH.