To get data about your installed graphics card hardware:
However, since the vga standard does not have any inherent compatibility with s-video, you will need to consult the manufacturer's spec sheet to be certain.
If your graphics card does support s-video, but needs a propriety driver to do so, you may be out of luck. Linux drivers are part of the kernel and unless the manufacturer provides a propriety driver for Linux, there is no way to include it.
A further note;
The pins used by non-standard vga cards for s-video are usually connected to ground on a standards compliant card. Connecting them to an s-video input will most likely result in a blank, black screen as the display will interpret this as a 'flatline' signal rather than as no signal.