In that case, I would probably just stay with the .org. Is being a part of the Apple affiliation program essential to your business? If so then I would consider trying to find a different domain.
You will probably struggle to rank in the main English language territories with a .io domain. I can't recall ever seeing one in the serps and hadn't even heard of it before this question was asked!
Don't be mistaken into thinking that 301 redirecting your old domain to the new one will instantly get the new domain to the same rank as the previous. It doesn't quite work like that. Of course, this will depend on many factors.

