It was the big Game of Thrones complaint for 2014: you couldn't buy episodes of Season 4 on iTunes in Australia. Panic no more, Apple lovers: it's finally available.
The pricing on iTunes is the same as on Google Play: $32.99 for the whole season (including extras) or $3.49 per episode (for HD copies; SD is $27.99 for the season or $2.49 per episode).
So if you want a legal copy and prefer your entertainment in the iTunes world, go forth and download. If you're not tied to Apple, there are lots of other legal options. If you'd prefer hi-def physical media, you'll have to wait until early 2015.
Game Of Thrones S4 [iTunes Store]