1. Open the image, i wil use this one ( not very good but it is aceptable :P )

2. Now select the part of the image that you want to change color

3. Now keep the selection and add hue, Layer> New adjustment layer >Hue/Saturation
Be careful! you have to select the same settings4. Now you should have something like this

If you have troubles, you can use the eraser tool ;)
I hope you like it ^_^