I received a written reprimand for complaining to HR about being bullied & Harrassed by a coworker

Question .... I work for a company as a salesperson and have been bullied & harassed in the workplace for several years by a co-worker. I have gone to HR after he continually put my safety at risk by locking access to fire exits, almost hitting me with his vehicle on work premises, deflamation of character to my potential prospects, being rude to my prospects & clients (those I can all prove with documentation). There is much hostility & annomosity in the environment. 6/12/15 the coworker approached me confrontationally and hollered at me for closing a door when I had a client in my office. I did not respond to him, but sent an email to him, my manager & HR Dept stating that I did not appreciate him hollering at me and the door was closed to block out the echos in respect to the rest of the office so no one's day was not disturbed by loud conversation.

I received a reprimand today for the inability to get along with coworker. The last time I complained about him being rude to my prospect, rude to another client, and violating company policy by smoking out the front entrance of our office (not a designated smoking area) clients will have to come in through a cloud of smoke & one of my clients had cancer ... I received another written reprimand for a dress being too tight or short.

My Mgr told me today that He has been trying to keep the issues away from HR, but now that I notified them he needs to write me up. He also said that this is the "beginning" and implied taking steps towards my termination; "which he does not want to see".

I make decent money there; but lately my sales have been down....since I filed the complaint about this coworker intentionally putting myself in harms way (fire exits & almost hitting me with his vehicle).
I've gone to my Mgr, I've gone to the HR Department, and now I've been written up (2X) (& implied termination) for him doing these things to me.

I don't know what to do, I've endured this bullying, this animosity, this hostile treatment & environment for such a long time. I had even told HR that a feared him, because of the animosity and me reporting him.

Please advise me of my options. I am a single mother and cannot afford to lose my job.