To Play Medieval 2 Total War You need a 1.1 pixel shader graphics card or higher How do you get your hand on one of those

You have to buy one. Those supporting PS 1.1 are really cheap now in bazaar. Even the cheapest (25 dollars in my country) new ones support Pixel Sader 3.0 or even 4.0. But the support of a technology doesn't mean it's powerful enough to run it smoothly.