Don't know if this is too late, but we stayed at Rezdenza Ave Roma on the Tiber River. It is a 5 room hotel about 1 block from Piazza Navona. Very nice, very quaint. The staff is outstanding and locationt is wonderful. It is very reasonable and most highly recommended. Also you can get a limo service from the port. I would not stay near the terminus due to higher petty crime rates.
Have a great time!