As I have never used vista (only for a couple of weeks or so). I failed to understand it primarily that the network notification icon you are wanting is of Windows Vista ! The second screenshot is not of windows 7 . Notification minimizer, volume icon, etc all are different, Aero peek button is not present there. So it is Vista, and here goes the proof ! (The screenshot is a random one, clooected from net) .
So, I guess, you did not have this network icon previously , in your windows 7 computer.