Getting Audio to Head rest mounted LCD TV's

[biffa]

I,m sick to death of scooby doo, chipmunks and ben 10 on long journeys.

I have a Cheap Ripspeed DVD HU, like this Halfords | Ripspeed DVD732B Single DIN 3" In-Dash DVD, MP3 CD Player

And a pair of Ripspeed Screens mounted in the head rests, like these Halfords | Ripspeed 7" Widescreen Headrest Monitor

My problem is i have to use the cars sound system for the kids to hear the DVD's, there are preouts on the stereo but the wont run head phones to the screen.

Ideally i need a mini amp with RC connections in and out and quite low power as i don't want to make my sons ears bleed.

Can anyone suggest a solution? I'm not opposed to making my own if someone has a circuit diagram.