Whilst the GTS 450 would be capable of playing skyrim (my laptop with a gt330m could play it at reasonable settings), unless you are getting a very good deal on that particular card, I'd look at something more recent.
The 7750/7770 or the GTX 650 (ti) are current gen cards that are in the same price range as the GTS 450, but have better performance and much lower power draw.
If you give us a price, your current system spec (include PSU) and a website(s) that you prefer to buy from we'll be able to help you much more.