Zook,
Can you hold a a screwdriver, hammer and nail? If so, the easiest way to get more power would be to get a flat top piston and valve from Mountain Air custom airguns. You need a hammer and punch to drive out the pivot pin to replace the parts.
You might talk with Roy at Mountain Air. He may be able to do the work for you. He can also re-crown the barrel for better accuracy. There are others who do this kind of thing too, just can't remember who right now.