Using US currency

[Mugsy]

OK, so if get sufficient cash in the RMAH, I'll get the Diablo 3 expansion (lets assume there will be one) using Blizz bucks. My RMAH sales have been in US dollars... can I still use them or do I need to change to AUD in order to purchase the expansion?

I've never used the Blizzard website to buy digital copies of games... total n00b to this.

[Linxus]

Go to http://us.blizzard.com/store/, browse for items, click buy item, log into your bnet account when asked, and select payment method, of which Im guessing BlizzBucks will be one. Everything associated with paying for stuff on BattleNet involves USD AFAIK.