If you do not intend to download windows media player 12 , you can always try to use the skin of Windows Media player 12 on Windows Media Player 11 ( Vista ) to get same kind of look and feel. Remember this will not convert your media player in Vista to Media player in Windows 7.
iurst thing first, Backup you registry first because This skin requires you to change system files and registry entries. In case something goes wrong you will need it.
Download it from here