I had a similar problem last year when the temperature was fluctuating up and down. The leaked water damaged some of the dry wall in my finished garage (my house is about 5 yrs old).
It is very hard to fix the problem while there is ice on top of the roof. You may further damage the shingles on the roof if you try to work on the problem now.
After the snow was completely melted in the spring, I sealed the potential leak area, between the shingles, or between the shingles and the metal rain collection valley, with Silicone adhesives and silicone sealants (I used a total of 6 tubes, at around $5 each tube, from Rona). I have no problem since then.
Unfortunately I had to redo some of the plastering/taping on the damaged dry wall.