When you say "brew at 50-60 f", I assume you mean ferment and condition. I fthat's true, yes that's a bit on the low side for an Ale. Typically, you should be between 60 and 73 or so. Technically, the yeast will work at slightly lower and higher temps, but why take the risk.
I'm not sure you'd want to use a heater, since that will result in gretaer temp fluctuations that can create some off flavors. You sure you can't find a closet or some place with ~65 temps?