How to apply a material to a noise zone? Hello Blender Stack Exchange people :)

I'm a huge beginner in Blender so excuse my question if it's dumb ^^

I've got this going right now : 





This might seem a little dumb, but I'm struggling to change the color of the lens ONLY on the spots covered by frost marks... Please help ? ^^'

Thanks in advance :)

EDIT : This question has been answered, but here's the .blend file with the old and the new (wanted) material :p

Blend file (forgive the name, I didn't have any idea of what I was going for when I started ^^')
Here are two ways of doing this, both are using Color Ramp with Constant value, and both can be changed to something else and with white value (from Color Ramp) you can control how much colour will affect area.

Mask between two shaders:

This is best option if you want to have not only different colours, but also different shaders assigned to "frosted" area. 



Different colours for one shader:

This is best suited if you want only to change colours.