Extra 3 months? Did i miss the press release saying so?
There are no official statements from Apple. In fact, there never are. Only within a week of the actual release of a product, if anything. But since iOS5 was just showcased at WWDC, we can assume they will want to mature their iPhone 5 OS first. And thus we can guess we'll see the next iPhone around September.
But there is no such thing as a '4S'