Insulation, Radiant and Vapor Barriers - Master Bedroom Cold above Garage - Again

the never ending question. i have been told 2 different things. my master bedroom is cold in the winter which is above our garage. currently there is about 1.5 feet of space b/w the ceiling of the garage and the floor of our master bedroom. the garage is finished with drywall and and r-10 insulation resting on the ceiling of the garage, with no vapor barrier. i have been told to take everything down and in put in a vapor barrier next to plywood floor of master bedroom, then insulation, then vapor barrier then drywall and finish and i have been told to do the reverse, in the same order, which is put insulation then vapor barrier and then drywall resting on the garage ceiling instead of attached to the floor of the master bedroom. One way will produce mosture in the cavity i am told >? so basically i am confused as the correct method of installing the v/b [i know it has to be on the warm side] but i was then told that this would produce a mosture buildup and rott the 2x10 supporting our master bedroom.

thank you for your help

Gabe