I hope someone can help with this

Hi this must be worrying for you if you are not living in Italy. I am afraid it is true that it will take a long time to enforce an eviction (sfratto), but you should get your lawyer to start the ball rolling. You need to record the fact that as you are aware of the situation you are taking steps to rectify it, also to remove or limit any civil liability as the owner, if there are any accidents in the property (responsabilita civile). 

Get moving with the legalities. If they stay there long enough, they get usacapione - the legal right to stay there forever. You also need to go there and, not using any illegal means, make life uncomfortable. For example, take the roof away as part of a long term restoration. Complain to ASL that the toilet facilities are in adequate (if that's the case) etc. There are many things you can and should do - ask the police for advice.

Yes I would go there as soon as possible -it may even be worth offering the woman some money to get her out -cheaper that having to get builders in to take off the roof.If she has been offered somewhere to go then that is helpful to know -can you offer to take her there?Whatever happens going down the legal route is a last resort.   

Just follow Charlotte Oliver's advice. She really knows what she is talking about. There must be a legal record of your acknowledgement of the situation and that you are taking the necessary  steps. This type of problems cannot be solved by talking.