Sadly, you are not in a good spot. I hear people using the terms "Rent-to-own " and Lease/Option too often and most of the time incorrectly.
In some cases you will need all the items as in a normal lease: Sec Depo,First months rent, Good work history, good credit, etc. You will also need some money offered as the "option" Which you will lose if you do not buy the home. Based on the info you have provided and the fragile housing recovery and job market , I don't know if a seller would consider you.
I have to agree with an earlier answer. Consider staying put and rebuild your credit to the point you can buy in a tradtional deal
PLEASE be careful and use lawyer if you plan on entering any type of " out of the box" contracts.