Go to bottom left, go to the launch bar, and type "dxdiag" and press enter. It will be opened a window whit your general specifications about your PC. THere will be a seccond tab talking about your GPU (video card) whit the info you are looking for.
If your using a laptop I doubt very much if you have an external video card, most laptops use a mobile version of the gpu you find on external cards but soldered to the motherboard. There are external cards you can get but more hassle than they are worth. Unless I am misunderstanding the question.