How to change color of a complication

I am just wondering the proper way to change the color of a complication. For example, the battery complication that is in a circle and the base color is gray and the battery depletion color is black or transparent. How can I go an change the gray color to green, yellow and then red as the battery depletes?

Can I do it right from the GWD or would I need to go into the folder on the computer where that complication is and use photoshop or whatever graphics program to change the actual file color?

Any help would be greatly appreciated.

Thank You!

Using Photoshop or any other image editor i s your best bet

GWD has tools for adjusting color and lightness of inserted images.
But it can not do wonders, if the source image is too dark or without saturation.
Did you mean this complication?