S.M.
D.,
I would suggest getting a saline Nasal Spray like Simply Saline brand Allergy - it's got a higher salt content than the regular and so is more drying. My DD usually tolerates the gentle mist pretty well. At 27 months, she likes to do the spraying herself now, but most of the time she manages well.
Cold meds are not recommended for children under about 6 now.
Does she know how to blow her nose? Work on that skill. You can incline her bed/crib to a 30 degree angle to help with drainage at night.
We also use the mmenthol vapor bath at bedtime when DD is congested with good results.
S.