I need help on finding a video in and video out through USB

[B_BODY_1]

I am going to be using 2 different laptops in my car, so anyways I want to only plug in 2 things the power cord and a USB cable
Through that USB cable I need the following

Video and stereo in
Video and stereo out
Extra USB inputs<>which is the easy part

So I was thinking about getting this Kensington K33367 docking station
http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1

and then a capture device that has good quality
Does any one have any ideas on what (+cheap price) to get??
Thanks……