An S-video connection is part of the vision of a TV setup, not sound so, it's a graphics card upgrade you require for this, not sound card.
This is going to cost. Before you lay out oodles of cash, have a look at stand alone DVD players to connect to your television. You can get a DVD player for less than £40 (e.g. click here ) which is less than the price of a S-video graphics card.