Yeast were probably pretty stressed, as that's serious underpitching, according to MrMalty (and assuming it's a 5 gallon batch). They might have petered out before they finished. What is the current temp? You could try bringing it up some (say around 70°F) and gently swirl the fermenter to re-suspend the yeast. Also, what was your mash temp? If you mashed high, this might be about as low as you're gonna get. We really need more details to narrow it down any further.