Outstanding deal for that hotel!

If you guys are comfortable doing the "train thing", and don't have much luggage, there's that. From BCN you'll have to switch trains in Sants, and the trip takes around 45 minutes to the Passeig de Gracia station. Then you're about 3 blocks from the hotel. Honestly, I've never done it, though it is a lovely tour of the industrial wasteland to BCN's south.

Cabs are cheap and plentiful here. If I remember right, it's about 20€ to the Calderon and 15-minute trip without traffic.