HELP - Fermentation has stalled

Saturday night I brewed my first batch, a pumpkin ale, and brought the carboy down to my basement for primary fermentation. Within 12 hours or so (Sunday afternoon), fermentation had begun. Sunday night I noticed that the temperature of the liquid had begun to fall (since the basement is so cold), though fermentation was still occuring.

I had put a sleeping bag around the carboy as soon as I brought it down to the basement, so I went to sleep Sunday night hoping that the temperature would soon level off. To my dismay I woke up Monday morning to see that the temperature had fallen to 59/60 F and fermentation had stalled.

Unfortunately I didn't have time to take action until after work - I attempted to warm it back up with a spaceheater, though to no avail. Ultimately, around 10:00 PM I brought it back upstairs and placed it on top of a heating vent for an hour or so. This raised the temperature to about 65, so I moved the carboy under a table and wrapped it in a sweatshirt to protect it from light, expecting to see fermentation when I awoke this morning. At 9:00 this morning the temperature of the brew was 67 F, but fermentation still had not restarted. Also, there was really no Krausen (where there was before), just a very thin layer of yeast on top.

Should I continue to wait it out or do I need to take further action?

Continue to wait. Just because there is no visible signs of fermentation doesn't mean it's not happening. Give it some more time (a week or so) then take a hydrometer reading... wait a couple more days and take another reading. Consistent hydro readings will be your only true sign that fermentation has ceased. on a side note, according to Papazian in the Joy of Homebrewing, 2 to three day full fermentations are not all that abnormal.