Need a quick assist to place a new face in a PNG file

Don’t have time to learn how to do this at the moment. Can someone change a face in a PNG for me ?
The model SKP is good, so just need Simon Masrani as the model face. Model clothing is just fine as is.
I can darken the skin by using a New Layer > Multiply and Black as a color.
So just need the face replaced.

Walking_Man.skp (7.3 MB)