M1,
I had similar problem. I tried to heat my garage, no good. I finally built a spray booth using and old fan from some electronic thingy and a plastic tub. I vent the fumes out of the window via a 4" dryer hose. My wife through a fit about it, but I finally won. Come to find out she didn't have anything to worry about. No paint fog, no paint on the walls, no smell permeating the house, it's all good.
However, If that option is out, Acrylics don't do well under 60 deg (15 c), but like Bish said, I can spray enamel lower than that.