How do I get my insane ex-crackhead neighbor to leave me alone?

More than a year ago, an older couple (50's) rented the house next to mine. When they introduced themselves, the man leered at me, so avoid him. The woman became increasingly odd over time. First, I noticed that a lawn decoration of mine was on their porch. I went in to ask about it and she said she "didn't know whose it was." We have a shared driveway and that was the first of several things they've taken from that side of my house and left in PLAIN VIEW in their yard! I approach them each time they take from me and thought that perhaps it was a joke to get me to talk to them. They give my things back and of course, I don't leave anything in my yard now.

I've also noticed that she's often bloody. She'll approach me with blood in her mouth and on her arms. I've asked her if she needed help and she told me she had just eaten cinnamon candy. I pointed out bloody spots on her arms and she just rubbed it in. Later, she hinted that they used to have terrible fights. Once as I was about to pull out of the drive, I saw her in a red negligee carrying a bucket in each hand. She slipped and fell so I got out to help her and she was bloody then too. She is always staggering. It may be due to a back injury...

For a while, she'd ask me to have a garage sale, a garden, a lounge area with her and would ask me over for coffee. One day I decided to came over for coffee after seeing how thankful she was for a frog ceramic I gave her because I was cleaning out my home and had never really found a place for a frog wizard complete with purple hat. I knew she liked frogs. She talked my ear off. She never wants to let me go when we talk. She has odd mannerisms and seems to have chaotic energy. She also gets very defensive easily and can't keep up with her own conversation. She confessed to becoming a drug addict after being in a car accident that left her with a slipped disk. She apparently had ran out of pain killers and asked her friend to bring her something to ease her suffering. Her friend brought her crack (!!!!!!) and according to her, that led her to loose her job as a social worker, her home, her car etc. Her husband started doing it with her. Obviously this has damaged her brain. I then decided that I didn't want to have much to do with them and that it wasn't a good idea for them to know much about me. She hasn't let me go since that day!

She accosts me about every third time I come or go. Last night I pulled in and the doggone "Neverending Story" came on the radio, so I stayed in my car and ROCKED! She came out and peeked at me in my car! She comes out of her home every time I'm outside and starts many conversations. She's always at my door. One day, she knocked on my door 4 times in just a few hours time. I dread coming home or leaving! She runs after me yelling "Hello! Hello! Hello!" and that's the end of my peace. She never wants anything, but finds another subject to keep me before her. I've tried telling her I don't have time, or that I must go, or making my answers short. I understand she may want or NEED a friend, especially if she's being hurt at home, but don't think it's wise for me to befriend her. She's insane and says nutty stuff to me while nodding her head quickly to the side, bugging her eyes and fluttering her arms about. She has a nervous laugh, staggers like I said, and her eyes are always shifting around my home and every move I make. I become paranoid that she'll steal for me during a relapse. Their dogs are mangy and are allowed to run around the neighborhood. They bark at everyone and chase them. They behave as if they they were raised by crazy folk. I feel bad for them, but want to avoid them also. I own my home and told myself they'll just move in a year, but apparently they signed on for another. Bad blood between neighbors is something I thought I could easily avoid, but she's providing me with a challenge. How do I sternly stop this woman from always desperately wanting my attention?