Well for starters u can...... GET RID OF VISTA!!!!
Skyrim and vista or anny other game dosnt belong on a vista OS.
Well graphic card is about it when it comes to gaming.
My pc is 5 years old with a Duo core E6850 3 ghz, 4 gig ram, and a asus motherboard.
6 month ago i bought the 560 GTX TI SuperOverclocked, and with it i can run Skyrim on close to ultra.
As your pc specs seems better or atleast as good as mine, with expetion of your GPU. You just need a graphic card.