It's not very clear from your post what region your SE account is registered?

1. You have an EU copy of the game.
2. You have an EU steam account.
3. You have an NA SE account. (???)
4. You live in NA.

What you probably need to do is buy a new copy of the game from the NA region. I don't think SE will give you a new copy of the game. If you have an EU sqex account you'll have to contact customer service and beg them to change the region for you.