Need 320 x 240 vga out to second monitor

I have a sony vaio laptop with a vga-out. I have a 7" lcd monitor in my car
that accepts rca connections.
I have a vga to s-video/rca connector and an s-video to rca connector.

Only the VGA --> S-Video --> RCA --> Car Monitor setup seems to display
anything.
When I attempt to clone the screens, it just shows up black and white,
snowing/gittery and doubled. I take it this is because the smallest
resolution the vga-out is doing is 640x480 while most tv's have a max of
320x240.

Is there a way to shrink the resolutions to 320x240. I'm willing to do this
for the primary display as well to have this setup work.

Any suggestions, even pcm/cia video adapters (if there is such a thing) that
could output 320x240 would be helpful.

P.S. there is no s-video out on the laptop itself.

Thanks
Ken