Unity iPhone / ANdroid game to bugfix and update

We are looking for a developer with licenced Unity Engine/Toolset for iOS and Android who can bugfix and update our existing game on the Appstore and convert it to Android. The work needed to be done: 1. Find and fix a bug, where the main actor is falling into a black void making impossible to play the game further. 2. Change a small collision thing (character should be able to shoot through barb wires). 3. Change a game feature where enemies are shooting from off screen (maybe only for easy and normal mode) 4. Sometimes weapons fall behind fences or towers making them impossible to pick up (would be nice if it could be fixed) 5. Integrate iAD / AdMob through AdWhirl (removable by IAP). 6. Integrate IAP (In App Purchase) 7. Build an Android version 8. Integrate GameCenter into iOS version 9. Integrate OpenFeint into Android version If we can work together and both sides are satisfied, a long term relationship is possible for developing the game further and starting other bigger projects.