I second D42's suggestion to just ride it out... in fact I sort of doubt that you'll get much of anything from adding enzymes in the primary; alpha amylase is really only very active between 155 and 165 F (Here's
a nice chart that demonstrates all the various enzymes & their functional temperatures), and beta only active a bit below that. At primary fermentation temps, I doubt you'll get any breakdown at all, or just a few percent at best. If you're going to heat it now you might as well re-mash and re-pitch.
David_42: I actually found a bottle of beta amylase at either San Francisco Brewcract (in SF, CA) or Fermentation Frenzy (in Los Altos, down on the peninsula); I don't remember which. They both do mail order, but neither of them list enzymes in their online catalogues... you could try calling and asking if they'll ship you some, but I haven't found any locally or online, either. Try sfbrewcraft.com and fermentationfrenzy.com.