Unfortunately the USA store will only supply to those who live in the US or Canada and who have a US delivery address AND a US billing address on their Credit Card.
[those who know have told us this to be true and I don't doubt this for a minute].

Therefore if the International Store has sold out, you will not be able to buy a RioCar from Rio directly.

However you should visit the "For Sale" forum on this BBS as a number of people are selling RioCars for various reasons.
[not all are trying to make lots of money from doing so].

You may also try Ebay - but the prices there will not be as cheap as the RioCar were at the Rio stores [which is why they sold out so quickly] and you would still have to get it shipped from the US.

So Sorry to be the bearer of bad news.
You should have been here a week ago :-(((