[Allons-y!]

Quick Google search showed me a few pages you might be interested in. I think, because your case is so specific, you might receive more information by calling a helpline. They can give you answers that they can promise are accurate--personally, because I don't know a lot about abortion and don't live in Australia, I would worry that the advice I gave you might be atypical to your situation. I'll try to ensure that everything I say is backed up by sources, but you should always check with the clinic to be completely sure.

This seems to be a really helpful site--they give information on procedures and cost, and they provide a confidential, free helpline. They also have a list of clinics that will provide abortions (and how far into your pregnancy they'll provide them for). All have telephone numbers, and I'm sure you could ring and ask them questions 1, 3, 4 and 5. Because the clinic you call will be the very clinic that will do the procedure, you can guarantee that they will be giving you the proper information.
http://www.childrenbychoice.org.au/nwww/abortion.htm

It says this about someone coming with you:

A partner or support person may accompany you into the clinic, and possibly attend the initial consultation with the counsellor (at your request) and will be contacted to pick you up when the procedure is complete. It is not usually possible for partners or support persons to accompany you throughout the medical examination and other medical procedures.

And about payment:

Payment for the cost of the abortion occurs before continuing through to surgery. Expect to pay between $300 and $800 within the first trimester of pregnancy (up to twelve weeks gestation), as prices vary from clinic to clinic. Some clinics also provide concessions for Pension or Healthcare Card holders. It will also be necessary to have a Medicare card at time of payment. Part of the cost of the abortion is billed to Medicare. If a Medicare card or number is not available, full payment will be requested.

This site http://www.abortionaccess.info/ may have more information you can use. It has a list of abortion clinics as well.

What I would do, is find a clinic near you and just give them a call or an email.

*hug*