Here's a picture with an example of what you're looking forhttp://www.windowsresource.net/cimages/dxdiag2.jpg
What you need to know are the top three things on the left side --
1. the "Name" of the card
2. the "Manufacturer"
3. the "Chip Type"
The example has the Name, the Manufacturer, and the Memory circled, but you can see the "Chip Type" (chipset) is listed right under the Manufacturer.
You can also check the right side of the tab for the "Version" and "Date" of your drivers.