Brugmansia overwintering - when to move where

Looking for advice. Was given a brug in the spring. Only one flower all summer until September when it developed 25 flower. We had a cool rainy week so I decided to bring it in the house. Enjoyed it for 6 weeks. The flowers have all dropped - should I move it to the unheated garage. I notice it needs water every second day or the leaves droop - should I move it, soak it and wait till February or March to move it outside?

 

PowellsWood Garden to the south of us in Federal Way describe how they overwinter their brugmansias: Overwintering Brugmansias - PowellsWood Pleasure Garden