Event Hall Acoustical Problem

We have a Band/Music Venue issue. We just opened a music club with great atmosphere, sound, and lighting. It is all going well. It is in a two story building we bought and upstairs we want to run an event space for weddings/parties etc. Problem is that we are getting too much sound bleed into the upstairs. I do not feel it is coming through the floor, except some low bass as I can feel some vibration (a little vibration is not a problem). The upstairs floor is ~3in of concrete on top of a full 2 inches of old tongue in groove planking, all supported by 30in steel I-beam. The planking and I-beams are the visible ceiling on the 1st floor. 18' ceilings. Outer walls of building are ~2ft thick and made of solid, stacked, and mortared brick. I am more concerned with the amount of, I guess, upper low range and lower mid-range 'music' that seems to be getting upstairs. You really can't hear words but can hear guitar beat/chords as well as some base. There is a large stairwell in back to the second floor... pretty much unfinished i.e. brick otter walls, sheet rock inner wall with one corner or 'U' the sound must go around. It has to go through two solid fire doors. In front is the same situation except no fire doors. I know that is a major source... but I feel there are others. What is best way for me to get a handle on this? Rent the sound meter and walk around upstairs and locate 'sound hot spots' like under doors, along walls, near stairwells, etc'? Couple of other questions.

1. The few sheet rock walls we have that could be barriers are not sound 'insulated'. Is there a way to 'blow' in insulation or do you have to add insulation to an outer wall.
2. We have a lot of 'dead' space near the ceiling of the first floor (bv. ducts, along sides), would it help to add some sound curtains and/or paneling up there?
3. Do you think it would help paneling the stair wells?

Thanks for whatever help you can offer. Cmitch47