I have not had good results with NACA. Hope is a great lender. There are also a few lenders I know that can do 580 scores. Also, there is chance of correcting the low score enough and getting a rapid re-score to get up to 620. Let me know of I can be of any assistance! Dont give up on buying a house!
Hope community credit union will accept a score of 580. You can also try naca b/c they don't have any special requirements and they will accept any score as long as you can prove to them that you can pay a mortgage. They also have excellent interest rates.
There are investors / hard money lenders you can try and find, some of them actually have reasonable rates. Try contacting some local real estate agents in your area, b/c they may have buyers they've worked with in the same situation as you and also may have contacts on the lending side to help get you the loan you want/need.