modify and recompile android app source code - repost for APEX

I have an android app source code that I need graphics changed on and i need the app modified a little bit just to get ideas on how to develop an app better with more features and a better app all together can someone help me with this? It should be a rather quick job as you arent doing any new programming yet really just changing stuff around so we can use this as a demo with our product research team in house only in helping us develop a brand new concept and app all together (which will be a new source code fully then) but we need this one done just for internal purposes!