Here's the thing, my sony vaio vgn z45gd has 2 graphics card, an integrated and a discrete geforce 9300m gs. i want to change my discrete graphics card however i am at a loss at which to get . something that is really good but not too expensive and not too big because mines a 13'1 inch laptop.

also, i have a few questions regarding graphics cards.

1)does a better graphics card heat up the computer faster ?

2)currently i only have a single 4gb ram but can i run a good graphics card with it ? my processor is intel core 2 dual 2.66 ghz.