Nice machine. I really like the cabinet. I have a Necchi BU and my latest acquisition is a Supernova Automatica which was only recently unfrozen. There is a yahoo group called necchisewingmachineclub that you can join to get more information about your machine. They're pretty strict on being on topic (and sign your posts!) but once you join and post an introduction you can join the "sister site" yahoo group called Necchi_Sewing_Circle. That group is for overflow files from the first group and in the files section, you can download a manual for your Esperia. There is also a service manual for the BU-BF machines which might have helpful information for your bobbin winder as it appears to be similar to my BU. You can also check the database on the first site as some members have parts for sale or trade.
Good luck in your search and with your machine. So far, I love my Necchis.
John