To select out the different colors, create a new layer and go to Select - Color Range. Click on the color you want to sample with the regular eyedropper tool. You can play with the fuzziness to get more of an accurate selection. Also, if you need to add or take away from your selection, you can use the eyedroppers with the plus and minus symbols next to them to do so.
Next, go to Layer - New Adjustment Layer - Hue/Saturation. This will load your selection directly into the Hue/Saturation layer so that you can adjust the hue sliders and change only the colors you want to change!
Refining Layer Masks
If you have small unwanted parts in a selection, you can always paint over it with a brush tool on the layer mask.
Tip: If you hold alt/opt and click on a layer mask, it will appear as black and white. This can be very helpful for seeing tiny stray colors in your selections.