I moved in with a roommate but i didn't sign a rental agreement

i moved in with one of my ex friend in January 1,2010 but i didn't sign a rental agreement but i gave her 316 for deposit. but no rent cause there was a 1 month free i moved out the the first week in march but pay the whole month of march when i moved out she said the she wont give me my deposit back until she moves out so i decide not to clean my room and i told her she could keep my deposit money cause i didn't cleaning my room and now she is keeping asking me to pay her 100 but she kept my deposit or go clean the carpet and i told her no cause she has my deposit money she said that the manager is going to sue me but i told her that the manager cant sue cause i didn't sign the least or can the manager sue me.
i live in oregon and we had a verbal agreement and i have witness please help me i don't know what to do