If that isn't an option, see if owner financing would be an option. Many sellers will offer that to you if you have been a good renter and have paid on time. The rate of interest will be higher, but having a record of on time payments can dramatically increase your credit score.
Let me know if I can be of further assistance.
Have you made attempts with local bank less than $50K smaller bank might assist you however they could require down payment 3.5% or more, 2 year employment, credit scores, debt / income in check.
Best resolve your credit issues move forward.
OR do you have a family member who can assist you ?
Would the property owner consider a lease purchase option then immediately work on credit scores?
Lynn911 Dallas Realtor & Consultant, Loan Officer, Credit Repair Advisor
The Michael Group - Dallas Business Journal Top Ranked Realtors