Thank you all for your support!!
As you advised, I decided not to panic and study my room acoustic as precisely as I can do it by myself.
I've already got the ECM8000 mic and downloaded REW. After few hours of reading REW Help Content and searching other forums I've found that the softwer doesn't actually work with my mbox 2… (how to setup REW using a MBox2 - Home Theater Forum and Systems - HomeTheaterShack.com
Any other software that will run on snow leopard and work with mbox 2?
I know there is FuzzMeasure for Mac, but it costs 150$… I wouldn't hesitate, if not all the other expences I'm facing at the moment. I've been searching the forum but it seems other software runs on windows only.