I'm sorry that this is going to be bad news, but I've got to be honest with you: You haven't described any wrongdoing by the property owner. Accordingly, unless there are important facts that you haven't shared which you can prove in court, then I don't think that you'd win a lawsuit against the property owner. To win a lawsuit against the property owner, you would have to prove that she did something wrong. For example, if you believe that the tenants should have been evicted, then that means you'd have to prove that the property owner had a legal obligation to evict them. But you haven't described any such legal obligation.
My suggestion would be to move to a new location where the property owner takes your complaints more seriously. I'd be lying if I told you that you have a good case based on the information that you shared.
I am truly sorry for the bad news, but please understand that it would be unfair to you (and unprofessional of me) to provide you with anything less than an honest response. However, if your concerns were not satisfactorily addressed, then please let me know and I will be happy to clarify my answer.
Also, despite the bad news, I would certainly appreciate it if you remember to provide a positive rating via the stars, as it is the only way that I'll get credit for answering your question(s). Thank you. :)