no. R/L RCA is stereo.
you're gonna need a sound card that supports digital out (either optical or coaxial) there are external sound cards that can be used with your laptop.
s-video is a bit crappy when talking about resolution.
it's highly unlikely the picture would be nice without using either a VGA input/DVI to HDMI on the LCD. I used to watch using my video card's s-video out ... fonts are unreadable, movies are "watchable" if you have low standards.
after deciding that s-video was really crappy, I got myself a VGA repeater and split the signal from my vid card to my pc monitor and lcd tv.
after seeing the fonts are still not "pc monitor clear", I got a new vid card with vga and dvi outputs ... i then used a dvi to hdmi converter to connect to my lcd tv. that's as clear as it can get, but still not at par with dvd/HD quality.
i know these are PC solutions but I don't know the outputs of your laptop, my macbook has a mini-dvi, i believe most laptops have vga outputs