Best answer by Mathis
First off - great to hear things are working out so well with your streams in SoundCloud SoundCloud currently does not provide insight how many users ended up clicking on the buy button to get to your Album on iTunes. Maybe iTunes provides insights as to where the referrals were coming from?
Or, you might be able to gain further insights through other 3rd party services (since we don't develop those, we won't be able to support though).
Sorry, probably not exactly the answer you wanted to hear, but I hope you'll find a way to receive more insights.