I'm so sorry your having a hard time. It does take time for meds to reach the therapeutic levels and i know it can be frustrating. Try your best to give it a bit more time then maybe adding something else or trying something new may be an option. Maybe you could encourage your GF to read a book or do some research about bi-polar, at the top of this site there is a reading list of books about bi-polar some are meant for partners, spouses , or family members to read about how to help someone with bi-polar. I'm glad you told your pdoc about the voices getting worse but did you discuss the worsening suicidal thoughts? If things get to be too much you can take yourself to the emergency room.
Stay safe
tina