I want to add segmented control to the navigation bar but also keep the title and buttons, like in iOS 7 Appstore purchased section (example)
I have tried adding seg
I have tried solving your problem using another approach since using a navigation bar only didn't seem to work out (maybe it's because the AppStore app is using a private api but I'm not knowledgeable enough to tell for sure...) Anyway I simply used a toolbar placed just underneath the navigation bar on which I added a segmented control, all inside a regular UIViewController.
This is what it looks like in Storyboard:

And this is the result in Simulator:

Just be careful to offset the table view down to account for the vertical space used up by the toolbar. Hope this helps!