You cannot do anything until Spring after the snow thaws. Depending on who did the roof and how long ago, you may be looking at not a repair, but a full tear off and replace. Are you in Alberta, or Quebec? If you typically get 1 foot of snow on your roof, you may be better to go with a steel roof, that looks like shingles, but holds up better over asphalt shingles.
The roofers on here are very qualified and very thorough with their advice. You need a new roof........period. No one can replace it now with snow and cold temps. Once the weather warms up, get some estimates, pick a quality roofer, and giterdone!!! There's no product I know about that you can slap on to a leaky area in the middle of winter that won't cause a problem later when you have to do a partial or full tear-off and redo the roof. Jagans is on the money, contain the water in a trash can for now.........bout all you can do.