Thanks for the advice everyone.

I went and had myself fitted last night, and bought two lovely Hot Milk bras. One's cream and blue, the other one pink and black. They feel pretty comfortable, and I'm glad I finally got around to doing it.

I went to the Bra Bar in Perth, as recommended in another thread, and the fitting lady was lovely.

Oh, and I've gone up to a C cup, which I was quite surprised at. But yay!