What do your mean by "the find my phone app was deleted" - deleted from the stolen phone? How do you know it was deleted. Besides, the Find My iPhone app is only used to track other devices, it does not turn on the Find My iPhone service. To do that you would have needed to go to Settings>icloud and then turn on that service by switching the slide to ON. If you didn't do that, then the Find My iPhone service will not help you.