I would start out in the yard, making sure all of the downspouts are piped to get the water coming off the roof at least 10' away and downhill from the foundation. When the ground is frozen and saturated, it is going to come in wherever it can.
If it is groundwater, it is clean and it will not hurt the concrete. Plug leaking cracks with hydraulic cement. Keep everything off the floor. Run fans and a dehumidifier to help dry the area. If the water is coming from underneath, a sump pump will help, but taking care of the exterior grading and runoff should come first.