Alternatively, you could acoustically treat the space using acoustic foam or rigid fiberglass. This page has tons of good info:
http://www.ethanwiner.com/acoustics.html
Ben
Alternativly you can use some cloth which might be cheaper or free from theatrical places. But if time left and concept admits it, I would go with the play-the-room suggestion as this could augment the perception of your sound.
Cheers,
Malte