There are 3 parts to a mortgage approval:
ability to pay -your income
willingness to pay -your credit score
collateral- the property
If you are missing any part you do not qualify for a mortgage. Go to your local non profit housing group for credit counseling. They will go over your credit with you and tell you what you have done wrong and what you should be doing. Listen to them and when your score is 640+ you will qualify for a mortgage.