I get want you are looking for now...

EggHead gave good adivce, for the video card you are looking for Video-In Video-Out or VIVO... ATi brand has several models of VIVO cards and others called All-in-Wonder... check those out...

Nvidia cards have a similar thing too but not sure what it is called.

If a new video card is out of your budget, then Egg's TV Tuner/Capture card would be your next best bet