We sat in the bathroom for awhile with a steamy shower running, or we boiled water on the stove & put it in the bathroom sinks. That really helped. Also, put a bath towel under the crib where you put the baby's head for the night. Our babies moved around a lot too. The elevation is enough to help, but is not so much that the baby would possibly sleep with his head lower than his feet. Just make sure it's not a real big elevation. We folded the bath towel into a square...like one would normally fold a bath towel, and stuck it under the crib...I think we used 2.
If none of that helps, you could get a cheap humidifier from Target or Walmart.