I wish I could help you but I have no clue on how to...
To be honest I'm not really versed in Ambilight, what I did was fidling with the different settings until I found a working configuration.
My setup is not the same as yours, I use an USBTV007 too but it is plugged in a scart, no HDMI for me so maybe your HDMI to AV is the culprit in this case.
Also to fix my color swapping I had to set "PAL" instead of "NTSC" in the V4l2 grabber configuration (but I had red and blue swapped, not like you).
Thanks so much for the quick reply i have managed to fix it, i set the configuration to RBG and set PAL on the HDMI/AV and has all worked, thanks so much.