Mortgage lenders require access to all three credit bureaus for each borrower. They use the mid-credit score. If your three scores were 649, 553 and 524 they would use the middle of the three scores, in this case 553.
Get with a mortgage lender that can help you figure out the most beneficial areas to work on to bring the score back up.
The average has to be 630 or above for a home loan.
You can start working on what needs to clean off your credit report by contacting the credit reporting agency Experian, TransUnion and Equifax. Another options is companies that will help you in the clean up of your credit report, like: http://www.ovationcredit.com/