Try the Hotel Enza. Not fancy but nice, very clean rooms, excellent bath and a convenient location. We enjoyed our 3 night stay.

Try www.laterooms.com. Type in your requirements--dates, number of people and click your way through to Florence, where several hotels are listed. If you click on the hotel name, more info is provided, including a link to the hotel's website. We used this site to book a hotel for a last minute trip to London, and all went well. I'd use the site again.

Try Hotel Colomba- go to Hotel site itself! Read reviews on Venere.com

Thanks all again for your help! I was able to book a room at the Hotel Columba in Florence, so we'll see what happens!