I played around with this for hours, took a detour with some background leaves that made it too complex to work. Too much thinking gets me in deep water so it's best to keep it simple like Delores showed. I got the dark indigo blue colors by changing the Hue/Saturation and the Levels settings and the Gradient Map is way fun as well.

My original colors are in this second image.

 

More variety by changing color settings :)