I've been through this with 3 kids. First of all, NO COW'S MILK. Dairy is very bad and very mucus forming and will only make it worse.
Next, if you have a nebulizer and have a local health food store close to you is get some colloidal silver (nothing over 20ppm) and put that in the nebulizer and have her breathe it in. It's awesome (I've used it on pneumonia without going to the doctor).
Another thing, is definitely a humidifier and put some eucalyptus oil in it, but definitely a humidifier. I usually mix the eucalyptus oil with a base oil and rub it on their chest to help them breathe and get congestion up.
Another thing is run the shower hot and sit in there with her for her to breathe in the steam. (If it was winter time, the outside cold would also be good.) You don't want your child to get to the point of seeing their chest cave in (to where you can count the ribs quite well) and not being able to breathe...otherwise the ER you will go for a breathing treatment from a nebulizer. So, if you don't have one, it's a great thing to have around for everyone!
The nebulizer and colloidal is actually enough to get them better (it's great for viral as well as bacterial). It's been tried and true in this household.
Dr. Mom. :0)