If you want to develop for iOS/Mac, you will need to have a Mac device to build in. This is an Apple requirement.
There are simulators for iOS and Mac, but they only go so far. For instance, you can't test anything with the accelerometer in the iOS simulator.
In theory, Eclipse has a simulator for Android, but it doesn't work for AGK.
So, eventually, you will need a Mac. I have heard of people talking about MacInACloud, but I don't know if it really works.
Part of developing for iOS is signing up with the iOS Developer Program (also required for producing an iOS app). And that involves installing stuff on your Mac and your test devices. Whether this would work with MacInACloud, I don't know.
Cheers,
Ancient Lady
AGK Community Tester and AppGameKit Master