Not strictly wicca ... but definitely the same genre is 'Anam Cara' by J. O'Donohoe.

I think it can get tricky looking for the wicca bible-equivalent. It's such a diverse tradition that pinning it down in one book is near impossible. Plus, by doing that you lose diversity, which for me, is one of the appeals of the tradition in the first place :)

I'm in Melbourne too. Have you tried the Esoteric Bookshop in Murrumbeena? There's some drivel, but you'll find some diamonds in the rough.