STEAM currency problem

So I have used, bought and put STEAM card in my STEAM wallet. And I have 50 dollars in my STEAM wallet. But when I want to buy the game, the game currency is in Rupiah (Indonesia currency) and STEAM said that my currency is not the same as the game price currency.
So after I redeemed STEAM card (and before attempt to buy the game) there were address form and stuff like that, that I needed to fill. I've been guided by the seller to put the address given by the seller, but the address was in US.

Is this where I did wrong? Put the US address in my info but I live in Indonesia? Or did I wrong in some other part? Will the Dollar currency change to Rupiah currency if I put my own address? Or should I buy the STEAM card that create for Asian region?
Can someone tell me where I did wrong?

Thanks :)