Hi and welcome to devnet,
For the bluetooth side Qt 5.5 is more likely what you are looking for. As for developing on both mobile platform, currently it's indeed mandatory to have an OS X system.
Virtualbox seems to only support Mac OS X Server (Leopard, Snow Leopard). At least it's what they lists.
Also note that to be able to test your application on your iPhone/Pad etc. as well as submit it to the App Store, you need to enroll in the iOS developer program
Hope it helps