What can I legally do after I was sexually assaulted by a patient in the hospital I am working at?

I am a CNA at a hospital and have been sexually assaulted/harassed by a patient (and convicted sex offender) with a history of inappropriate behavior towards women staff in care facilities (exhibitionism, sexual assault, inappropriate language). This patient is a frequent flyer and is known for his behavior, but I had never worked with him before. Upon leaving after providing care, he smacked me on the butt and said "don't work too hard dear". I was never told of his conditioned behavior until after the incident where I found it was a common and running joke in the hospital by all levels of staff. I immediately informed my supervisor and his attending RN and was not approached by either for the rest of my 12 hour shift to investigate or address the issue. I was only addressed when the patient harassed another staff member of more rank and tenure. My employer told me I could press charges if I wanted but because I had not documented the incident in the patient's chart I had no proof (neither herself or the RN had documented the incident) and I had not been informed until several days later of this requirement. Additionally the supervisor did not report the incident to HR as per policy requirements. A month later the patient was back and repeated the same offense against me. I told my supervisor, documented, and informed HR of the issue and lack of proper recourse and was told by my supervisor that I had approached her about the initial offense when "she was too distracted by the conversation she had had prior to me entering her office, she was unable to give me the proper attention and that's why nothing came of it". My supervisor's boss then told me that I needed "to reassess my personality as to whether or not I was right for the job" and HR said they "would talk to some people" but could not promise I would see any improvements or follow up. They did tell me I was not allowed near the patient anymore.