What to do with a hostile work environment situation?

Sounds like you have a choice to make - take your doentation and go to an attorney and make your claims against the company legal - or allow HR to do what they have to in order to clean up the work environment and hope that it truly does change the hositile work place, and if it doesn't, keep up on the doentation, and then go to an attorney - either way you stand to be in a win-win situation - at least from what you have presented.