First of all...congratulations! This is a very exciting time for you and your family!
The website I found that helped very much was:
I found my 2 midwives there. You should look near the area you are moving to. I did a quick search and it looks like the closest ostetriche (midwife) on the site near you is Rome. I think from the site though, you may be able to send a few emails and find someone closer. Otherwise, midwives are generally willing to travel a few hours(which would be fine...there will be time for them to get to you-they will also sometimes stay nearby when you are getting close). The most important thing is meeting them and feeling comfortable. You also asked about natural birthing centers and if I am not mistaken, the only natural birthing center in Italy is The Margherita at Careggi hospital in Florence. I found another center near WSiena but when I called them, they said they are not open right now.
I would highly recommend finding someone to stick by you and be on your side during the birth. Your husband is great but, they go through their own feelings during the birth...and you want a professional, that the doctors will listen to! I am not sure if you know but, there is a very high cesarian rate in the South of Italy(I don't mean to scare you...I just want you to be prepared!).
Please feel free to message me with any more questions. I have done tons of research and also have had a beautiful, healthy boy here in Italy:)