I had a dog who had acupuncture following a stroke. i'd say that she recovered to about 90% of her pre-stroke self, but to be honest, i don't know how much was due to the treatment and how much was just normal recovery. having said that, she was around 11 years old at the time and lived to be 16 .
i noticed some improvement following each treatment but it was more of a cumulative thing. she had extrensive acupuncture during the first month or so following her stroke, then we moved away so the treatments stopped.
good luck to Hannah and i hope she feels better
ETA: i've had acupuncture after i broke my arm and messed up my rotator cuff last year. they seemed to be effective and i generally felt the results almost immediately. they didn't last for that long, though.