Pre-order qn (EU ff14 copy, now staying Australia)

Tried to pre-order on the SE online store but it only had US adddress available but im now in Australia.

Another thing - I did not buy ARR from US. I bought the *original* albeit unused product code of FFXIV 1.0 from UK (for cheap) right before ARR was released.

My question now:
1. Do I have to get an EU copy of HW to correspond my EU ff14?
2. If not, how do I get it off SE online store since it only has US address?

You're probably on the wrong SE site. The Australian SE store can be found here on the European site: https://store.eu.square-enix.com/apac_au/ (and yes, it has Heavensward listed for sale there in Australian dollars.)