Hi suzyq40,
We were in Melbourne 5 Years ago for a period of 5 years and we had no trouble finding Galangal, we used to get in at the Asian fruit & veg shop at Parkmore shopping center and it is sometimes available at the large supermarkets like Safeway and Coles at Southland shopping center.
Just ask at Safeway and Coles and see if any of their stores stock it.
I agree with you on the homemade curry pastes the shop ones just don't cut it for me either, i always make my own and just last weekend made some Red, Green and Penang curry pastes.
This site is excellent for their Thai recipes.
http://importfood.com/recipes.html Cheers, Pete