Thanks for the suggestions so far. I've sent the Hotel del Corso an email inquiring about rates, availability and internet access. I've got a booking at the Hotel Tritone in the meantime (Via del Tritone 210, Rome, 00187) for 400 Euros inclusive for 4 nights. I can always cancel this one if something better comes up but at least this way I'm not scrambling for any place to stay.

http://www.tritonehotel.com