Can I use my security as my last months rent?
My apartment is in perfect shape and I know that I should get my full deposit back, however, I do not think that my landlord will have the money needed to give me back my security deposit. I know that if she does not give me back my deposit with in 30 days of move out, or notify me of repairs needed, that I have a case against her. However, I just want to use the security deposit as the last months rent and be done with her and the unit. She has been a nightmare for the past 5 months and I can not deal with her any longer.

No, but your landlord can. The main purpose of a security deposit is to protect the landlord against damages you might do to the property. A secondary purposes is to cover unpaid rent and fees.

So the decision of how to use the security deposit is solely at the landlord's discretion. You have no right to not pay the last months rent because the LL has your security deposit.