Comcast Motorola DCT2224/1661 STB and Widescreen

I just bought a Samsung widescreen HDTV and hooked it up to the DCT2224 via S-video cable. I've configured the TV to display 16:9. We've noticed that the picture is just getting stretched and distorted. I went into the setup for the STB but couldn't find a way to configure it to output 16:9. Could somebody tell me if this STB is capable of widescreen output and how to configure it if it is. If it cannot output widescreen, do I have to get a HD STB from Comcast to get the widescreen capability?

Thanks, guys. I'll be looking into getting an HD STB and connect it to the TV via a HDMI cable.