Save up $25 more and buy a 9500 or 9600 GT. A 7200 or 7300 is extremely slow. It will be worse than your 8400. They are 2D budget cards. Sure, the hardware specs say they can do 3D, but what you end up getting is a 2D slide show.
You have a decent system and want to throw a cheap video card in it, and then complain about how slow everything is? Spend a little more on a decent card. It seems you are not in the USA, but this deal (http://www.newegg.com/Product/Produc...82E16814121267
) shows you the kind of card you need. That 9500 will perform like a 7950GT, to give you a comparison you might understand. All for $50.