I would suggest checking the basic maintenance stuff first. When was the last time the spark plugs, fuel and air filters were changed. The change in climate will bring out any weakness.
there is an air intake tube on the car. Remove it and clean the passages there with spray carb cleaner making sure that the butterfly and main tube are clean. This will effect the idle speed.
When you take it in for the service be sure to have them look for vacuum lines that may have broken from the cold weather. Do you get any check engine lights on?
Sorry I haven't been more help.