There are strict time frames in which charges of employment discrimination must be filed. To preserve the ability of EEOC to act on your behalf and to protect your right to file a private lawsuit, should you ultimately need to, adhere to the following guidelines when filing a charge.
Make sure to take copious notes on date, time and what happened. I also suggest bringing a tape recorder every time you have a conversation with the abuser through your phone or a small recording device you can carry in your purse.
Then when you have proof, contact an attorney. The more proof you have, the better your case.
Try not to speak to them and email all correspondences and keep diligent records.
I was subject to harassment as a single female in my building as well, and I know what you are going through.