Well... Good luck with that. I tried that app, and although the app itself has a couple of good ideas, the voice on it is annoying as all buggery. I had it for 10 minutes and deleted it, knowing that I would rather enjoy the rest of my life without ever having to hear that voice - EVER AGAIN!!!
Get a piano teacher to help you... that's the best advice. Don't rely on Apps, as they won't help you actually identify ways to help you work out the correct answers.