In some cases, your credit score will increase about 90 days after proof of pay-off. However, with each infraction and depending on how many you have, it may not be enough to raise it up for the minimum you need. If your credit score right now is 500 - you got a long way to go, but if your credit score is 620...you might be close with your proactive measures.
Consult a reputatable loan officer. They are the ones that will be lending you the money and will help you on the right track. You have to play by their rules and a good lender wants to help you. It may not be an easy road and you may not get the tax incentive, but in the long run, it will be worth it for your future's sake.
You can get free copies of your credit reports every year from
BRC Realty Group