Update an existing android application

I have a simple game on android which needs a few slight changes. I need a facebook sharing function (sharing the users final score via a screen shot of the game) and a change in some of the game mechanics (will explain in more detail). Also, on some devices, there can be a substantial amount of lag which shouldnt occur because its only a simple game so I need this fixed. For an experienced developer, this is a very minor project and shouldnt take more than a few hours. The application is written in Java and I will send you the source code for the current version. Thanks for looking!