Good old fashioned steam. I'm on week 20 of a stuffed nose. The best way to ease it I found was to fill a bowl of hot boiling water with a little salt, throw a towel over my head, and stick my head over the bowl. I tried the nose rinse, but it doesn't do much unless it can get through your nose, which is difficult when its completely blocked. Invest in some good kleenex, your nose can get raw really fast.
They say it happens more often while pregnant. Try some saline nasal spray. Make sure the meds you are taking are approved by your doctor. I also invested in an air purifier, but it only helped a little bit. Apparently congestion comes with the pregnancy package. Maybe other ladies have other remedies.