Hi Concerned Cousin,
Welcome to the boards. If your cousin has been suffering this long, I would get her to the nearest Emergency Medical facility you can find. She should really be seen by a Neurologist as soon as possible, since this attack is so severe and has lasted so long. Be sure to take all her current medications with you to the Medical facility/hospital.
I found the website below, which is quite informational.
It would be more productive if you did an internet search for a migraine specialist from your location. If I do one from here (USA) I have to sift through a whole lot of junk (1,000s of sites) before I get to anything relevant to Australia. I would also contact your cousin's doctor and explain her condition. Stress the fact that she is having difficulty talking, which is why you are making the call for her. See what his recommendation is for the time between now and her next appointment.
Good luck and let us know how things turn out.