what I dd
it was a couple years ago, I had a bad ball joint and of course needed the whole arm. (Why, O BMW, why?)
My local import store had Ocap brand, made in Italy. Apparently they could not get Lemforder or another more or less OE brand. They deal mainly with the import car repair trade, small shop on a side street. They give me 25% off, lucky me, because I do some business there. Not nearly so much as the least busy pro, but I have a good relationship with the owner and the counter help are friendly.
You SHOULD be able to source a control arm locally. Going international will cost a bundle.