Dixie Louise's teeth

[maimaipg]

Dixie Louise is FeLV + and has gingivitis.  She has lost a couple of teeth (maybe from the gingivitis or maybe from the poor living conditions she had--she was a throwaway).  She has developed an odd odor to her breath.  I am trying to brush her teeth and she is on Interferon as well as some homeopathic/alternative meds.  Can anyone give me any advise on brushing a cat's teeth and on how to deal with this problem?  She is about a year and a half old (best guess) and extremely sweet.    Thanks