How do I lower the humidity in my non-vented laundry room?
Try installing a vent in the door, it will allow the room to breath.  Make sure the exhaust from the dryer is sealed all the way around where it exists the wall, then go outside and do the same thing.  Check the roof edge and make sure you aren't having water drain behind the gutter into the wall.  Then climb into the attic when it rains with a big light and watch for water. 

Also, get rid of that mold.. it's really bad for you.