Write an iPhone application

As this is my first time hiring someone to do an app, I would like to create a simple game, the game will be called 'Tap Billionaire'. The aim of the game is to make as much virtual money/coins as possible (Dollars or Pounds), by tapping the screen. Every time the screen is tapped, the balance of the account should increase by 1, they can make more than £1 per tap as they have the option to upgrade with their virtual balance. The upgrades consist of 'Double tap' where the amount doubles for every time they tap however, the cost of the upgrade should be high but reasonable and they can keep upgrading however the cost of the upgrade should increase. They can share how much virtual money/coins they have through twitter or Facebook as an automatic option so they can compete with each other. For every tap they do there should be a sound like 'cha ching'. The section that they tap can be a big bag of money or a coin, whatever looks good, and they background can be a bank account with their virtual balance.