There are several links on how to change hair colour and hue in this thread:

http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2722867

Quote - **  CHANGING HUE & COLOURS OF HAIR ETC:
**
Making Yuki's Red hair Brown with HSV node

Making Black Hair Maps Sandy Brown, or any red

Changing Hair Colour

change the hair color

Combating Black Shadows in Light Coloured Hair

More on Light Hair with Black Blotches

Making hair shiny in image-based lighting

Adjusting Material Hue & Saturation in Material Room P6

Adjusting Hue Inside Material Room

Special Colours in the Material Room> Quote -

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi