New CD key

I was global banned by BE and I was planning on buying the game off Steam AGAIN as I dont agree with buying off of the people who steal keys from people. Would I just need to buy OA again and use that key? Or would I have to buy both ARMA 2 and OA again? Also, would I even be able to buy it off Steam again? How? Whoever can help me, thank you! (:

You just need to buy Arma II OA