What will bring up my credit score in a hurry?

I have a credit score of 540, I need it up to at LEAST 600 by the end of the year to qualify for a loan to buy my house. I am divorced and alot of what was jointly is falling off ( a forcolsure according to Experien). I also got a new car in Jan and have been making my on time payments. Will this bring up my score so i can qualify for the house? What elese can i do. I don't qualify for credit cards. My debt income ratio is AWESOME, I make good Money!