well, the latest "to-be" version is 4.0, which ships with Vista. The latest available version is 3.0. For most games, like 90% of them, you can get away with version 2.0, and 1.1 is pushing it (I own a 1.1 video card )

To obtain a higher version, you have to buy a new video card that supports that version.

Unless you video card is several years old (like, 6+ years old), it probably supports v1.0, or v1.1. Look at the manufacturer's homepage, or a 3rd party site such as www.newegg.com, and see if you can find you card. Usually, they list its shader model version with its specs.

Good luck,
Raddaddy