Canon ixus 970is Colour Swap & Colour Accent Feature

Have recently purchased this camera and am trying to get to grips with some of the features. In shooting mode its possible to swap colours which is great & also to use the colour accent feature allowing you to highlight an object leaving it in colour and having the background in mono.
I would like to know if its possible to use these features after the photos have been taken. Can anyone help me here?
Have just come back from Cuba & got some great pics of old cars and would loveto use the colour accent feature.
Any help would be much appreciated.

It can't be applied after the fact in-camera; you'll have to use an image-processing program like PhotoShop Elements to do it in the computer.

Thanks Jon,
Was afraid this may be the case.