You cant use the existing screen to hook into your dvd player/console.
find a 7" screen, remove old motorised screen from is300 and make it fit your new screen.
Advantages are;
you get to hide the monitor when not in use, + show off when it comes up!
Disadvantages;
ive never done this, and imagine that the motor is some how tied to the screen, so some electronics may be required to seperate and make it work...
Regards
Jase