If you wish to change only the handle color then select only that part of the texture (selection rectangle) when adjusting contrast, and hue.
Shine on a blade is applied via the normal map, and though the apply_hilight/ Apply_modulate setting in NifSkope.
When the handle, and blade share the same NiTriStrip in the .nif file whatever shine you apply to one part affects the other.
In my last release (Nico's Gift) I separated the handle from the blade as two different NiTriStrips in NifSkope so that I could apply the shine to the blade but allow the handle to have less shine that better suits the leather that it is.
Shine when using the Apply_HiLight in NifSkope can be controlled by the alpha channel in the normal map. I have found that between 85% to 95% (of black in the normal map alpha channel) with Apply_Hilight gives a nice shine to metal objects.
http://img810.imageshack.us/img810/843/texture.jpg
In red notice the two separate NiTriStrips of the handle, and the blade.
In blue is the texturing property where the Apply HiLight is located.
http://img810.imageshack.us/img810/5038/texture2.jpg
In red is the Alpha 'K' value as located in Photoshop that I am talking about for tweaking the amount of shine in the normal map of a texture when Apply_HiLight is used in NifSkope.
It should render a shine in game like this>>>
http://firingsquad.us/albums/WIP_Mod_Pictures/Oblivion_2009_10_13_10_46_16_40.mp4
Notice that the blade shines but the handle does not.
Hope this was helpful, and not too cryptic