Navigation bar appear over the views with new iOS7 SDK

That’s not entirely true. There has been a new property introduced in iOS 7 that lets you adjust the layout behavior as in previous versions of iOS. Place this piece of code in your view controller, and you should be good to go! The space your navigation bar takes up should be accounted for automatically

 if ([self respondsToSelector:@selector(edgesForExtendedLayout)])
    self.edgesForExtendedLayout = UIRectEdgeNone;

You need add the above in your -(void)viewDidLoad method.

Note: You should be using the latest GM release of iOS 7 and Xcode 5 now since the API has changed from beta versions.