2. I think you need to purchase a MacBook, but I'm not sure.
How much do you get out of your apps atm? Ask yourself if the app is worth anything atm. Does it create revenue? If so, I'd go for iOS too.
As I am an Android developer without any experience with iOS, I'd suggest that you hire some freelancer to port the app to iOS if your app is giving you good revenue.
A friend of mine does it the other way around, he publishes games on iOS. If they are succesfull, he hires someone to port the game to Android.