If you import the video into AE CS3 there is a bluff technique you can use.
Import the footage into a new comp, duplicate the layer.
On the bottom layer apply the “tint” effect to make the footage black and white. Apply the “leave colour” effect to the top layer and select the colour you wish to keep (repete this process for multiple colours). You can then apply a levels and hue + saturation to the layer to bring out the coulor more and give it a styalized look.
Just a quick fix, but it works