Maureen, we are dealing with ice damming right now also. We removed the snow from the roof, took off the eaves and broke off all the ice and icicles and drilled holes in the soffits, but it was still damming up. Just last weekend we decided to put a fan in the attic and so far it is not dripping anymore and seems to be drying up. That is only a quick fix until we can get to the problem head on once the weather heats up a bit. I believe a "whirlygig" on that section of the roof, for venting, is what we'll have to install once spring hits. Our shingles are in good shape also, so that is not the problem. Venting is the problem.
Hope some of these tips help, but the fan was the major fixer in this situation.
Joey