What can we legally do if someone is harassing me and my husband?

I have a person that is harassing me and my husband. My husband used to rent a room from a lady and her husband about five months ago. When he moved out of her house to move in with me this lady because very upset. She started calling and texting my husband several times a day, saying hurtful things and trying to find out information about us. She has also written my husband hurtful letters, and posted nasty comments on his facebook page about our relationship. I am currently nine weeks pregnant, and two days ago, I got a derogative test message from her regarding my pregnancy. I was very upset by this, so I responded to her, telling her, in strong language, to leave us alone. Yesterday we came home and found a note from her on outdoor, saying that she would come to our house at 5:30pm. She drove to our house after this and pulled up behind my car, blocking it in the driveway. My husband came out of the house to speak with her, and I called 911. She started to yell obscenities at my husband, and telling him to get in her car. Mean while I was on the phone with 911 giving them her car information. When I told her I was on the phone with 911 she drove away. I let the dispatcher know that she drove away, and I hung up with them. After she left, I called the Council Bluffs police department to file a report. An office came to the house. He called her on the phone, and let her know not to contact us anymore, or come on to our property. She told the officer that she would be filling a charge of harassment against me, because of my response to her text she had sent be regarding my pregnancy. The office that came to my house made it clear that they were not to contact us, and that we shouldn’t contact them either. I am worried that this women will press charges against me for harassment, even thought I have never gone on her property, and the only time I contacted her was in response to texts that she sent me.