Do keep her head elevated at all sleep times and stick with the cool mist humidifier (it may be doing more good than you realize, and remember to keep her room door nearly but not entirely shut when it's running). But since she's had this persistent cough for 11 days and now it's invading her sleep time, please get her to your pediatrician. This could be a mere bug, it could be allergies (my daughter's mild allergies were diagnosed after very similar symptoms) or it could develop into something like croup, which needs medical attention. With kids this age, it's hard to tell, and these things don't always come with fevers--we always look for fevers as the sign to get to the doctor but that's not always the case. Also, a doctor should check her ears even if she isn't complaining of pain; ear infections are secondary infections that can happen when the goo from congestion settles in the ear and never quite dries up, and ear infections don't always come with a fever or even a lot of pain in every case. Do give any natural comforts a try, but at the same time, with a child this age, I'd have her checked out by a doctor since she's spent nearly two weeks coughing. Likely the doctor will tell you it's a bug and recommend some of the same natural remedies, but why not check. Good luck and I really hope you both feel much better soon.