I am an e-greeting card designer who is considering purchasing a capture card but want to be sure it can do what I want.

I want to be able to capture cartoons from either TV or a VHS VCR. I want to capture frames (from 12 per second to 1 per second) for about 10 seconds. Then I want to use those individual frames as templates for my own cartoon characters. This will help me animate my unique cartoon
characters using the motion from existing cartoons. For example, I want to make my cartoon sheep dog, Scruffy, chase its tail for an e-greeting but I need a guide to get the feet movement more realistic. I want to capture
either a cartoon or a movie of a dog chasing its tail and use that as a template for making each frame of my Scruffy.

I have a computer (Compaq Presario AMD-Athlon 600MHz) with a firewire and USB ports as well as video editing software that came with my computer. One person told me to just get a video card that has a place for an S-input hookup and another person told me to get a complete video-editing system.

What's the best way to accomplish this objective?

Any help would be greatly appreciated.