I congratulate UKBod on managing to get the TrenItalia website to work. It never did when I worked on the railways (and had to answer international travel questions) and it's still producing error messages for me now!
http://www.trenitalia.com/tcom-en
However the Die Bahn website (which brings together all European rail timetables) confirms the journey time and connection that UKBod has quoted:
http://www.bahn.com/i/view/GBR/en/index.shtml
(It doesn't have the fare for that journey though).
The two trains involved in the journey are both '2nd class only' so, unlike a few express services that operate within Italy, no reservation (or advance purchase) is required. However you MUST buy your ticket at the rail station (NOT on the train) AND remember to VALIDATE it at the machine by the platform entrance. (Unlike the UK, where tickets are sold for travel on a particular date, Italian rail tickets are undated. You MUST validate them before travel or face a hefty penalty if you fail to do so).