Girlfriends background and credit check for apartment?

Okay, here is my situation, My girlfriend and daughter are living in my apartment. I received a notice today from my property manager that she needs to have a background check and a credit check ran on her. So here is the deal three years ago she got a felony on her record for burglary (she was on dope back then). She has cleaned up her life and now and she's trying to better herself by going back to school and getting her bachelors degree and becoming a drug and alcohol counselor. Anyway, I'm afraid when she has her background check done on her that she will be told that she can not live on the property. My question is what options does she have? I'm thinking she should write a letter explaining her situation and show evidence that she is trying to better herself by attending college. What do you think will happen? Also what things should we do in explaining our situation.