I can tell you from personal experience it does not take long to get your score up. You just have to focus and make little sacrfices but it is well worth it. I am on way to homeownership with less worries.
Once your credit score is higher you can qualify for an FHA loan.
If your looking to purchase in Georgia you can receive downpayment assistance from the Georgia Dream Program and link it with Cobb County Housing Inc. this is 14,000 or more downpayment assistance.
Please view the website as they have various qualifications.
( Georgia Dream ...Clark Howard's site)
(if your purchasing in cobb county you link the 2 programs)
(if you wish to purchase in the city of Atlanta up to 14% grants)
If you not in Georgia, contact your Community Affairs Department in your City and ask about progams for first time homebuyers.
Hope this helps.