Your itinerary gives you ONE full day in Florence and 2 partial days - not really a lot of time to see the sights and to make it to any wineries.

You might want to look at going to one of lakes instead (Como, Maggiore, Garda, Lugano). If you really want to go to a winery, then you might look at the Bergamo area. It is about an hour outside of Milan by car and seems to have several wineries around.