lets start with the important bit the water, you need to put in coolant and tap water half and half would be just fine, if you do not do this and you drive the car you will break the head gasket and seize up the engine, any motor factors will have the coolant and will put it in for you.
now for the airbag light this could just be a faulty connection or you may have to get a mechanic to reprogram the ecu this will cost around 40-50 pounds in u.k or ireland around 60 euro, and for the rear boot i would think its a loose hose as bravo's dont have problems with this.
hope these answers help.....
micheal
June 2009