Hello. I will try to assist you.
So you have an oral lease with her basically? How long as she resided there? If she has been there over a year you would need to provide a 60 day notice, just so you know.
I have dealt with matters where clients have been in similar situations. In my experience the situation will just fester and get worse if you allow her to stay. You have served a 30 to vacate. Assuming that was a proper notice (as opposed to a situation where a 60 day notice was indicated) and that your service of the notice was proper, I would also follow that up with a 3 day notice to cure or quit- wherein you list all of the various lease violations and demand she cure them. If she is late on rent, I would also serve a 3 day notice to pay or quit.
When you file an eviction you want to be armed with as many reasons for evicting her as possible. It does not sound as if rent is an issue or that the code violations are significant enough to warrant a judge finding the property to be uninhabitable (they have to be pretty significant). Moreover, if the property were uninhabitable her remedy would be to either terminate the lease herself or withhold rent, which it doesn't sound like she has done.
I know she is threatening to cause trouble if you move forward with the eviction, but in my experience you simply can't let this fester. If you can't strike a deal for her voluntarily vacating the property by a date certain you should proceed with an eviction. When she raises various issues before the judge as defenses- pressure to provide sexual favors in lieu of rent, retributory eviction, etc. she will have to offer proof. Simply throwing it out there should not be enough to prevent an eviction where you have followed the proper notice procedure and testify to the court about multiple breaches of your verbal lease.
While she is quick to threaten you, she is also risking quite a bit if it goes to court. If a judgment is entered against her it could severely impact her ability to rent another place in the future. That is a good thing to remind her of, if you try and negotiate with her.
A few final words of advice. In the future I would use written leases and, with respect to her, I would try to have a friendly third party with you whenever you deal with her in person from now on. That way you have a witness who can refute whatever wacky claims she tries to make in court about any conversations you have with her in the future.