Add Gamecenter Leaderboard and in-app purchases to existing app

I have a quiz app for iPhone/iPad which is nearly done. It has been slightly modified from an existing source code, and I`ve attatched the documentation that came with the source code here. My modified quiz has 250 levels (questions), and no categories. The only remaining things are: * Adding in-app purchases (4 different ones. 3 consumable, 1 non consumable). The consumable ones will give the user a set amount of coins, while the non-consumable will remove all ads as well as give the user 500 coins. * Adding a Gamecenter leaderboard. This should be set up something like this: - the user starts each level with 100 points. For every second he uses, 1 point will be deducted. So if he uses 30 seconds on a level, he will recieve 70 points. - if the user spends more than 100 seconds, he will still recieve 10 points when a level is cleared. - users should be able to play levels as many times as they want to improve the score. * Make the "restore in-app purchases"-link relevant to what I mentioned above. If you have any real interest, please write DEXTER somewhere in your bid. Also, the amount you specify should be the EXACT amount you want me to pay you for this project, NOTHING MORE NOTHING LESS. I will not pay a dime until the project is complete. As you can see from my history, I have only positive feedbacks, and always pays when the work is done. I have planned several different apps based on the source code the winner will be provided to work with, so this might be a long time working-relationship. And finally, my budget for this is around $50, so please have this in mind if you plan to bid a lot more than that, cause you`ll only be wasting my time. Thanks.