It is so hard when they are so little and have stuffy noses! One of the best thing that works for me is steaming up the bathroom and sitting in there for a while.It helps loosen everything up. I don't know if you're breastfeeding, but I find doing that in the bathroom when it's steamy helps my kids force a little pathway through their nose. Offer plenty of liquids like water or diluted apple juice if she won't take water because that can thin out mucus. O.J. can make them more flemy. Dairy can make the mucus thicker so hold back on it if you started feeding that already.
Another thing to try is to get an inclined sleep positioner. I think I got mine at Babies R Us, maybe Target. It is a foam wedge and it comes with to other foam pieces that that velcro onto the wedge so your baby can't roll over. You can also put Alyssa on her side with the positioner-just make sure the velcro pieces fit snuggly next to her. Being in a more upright position makes it easier to breath when they are congested-and I found with my kids that being on their side worked better.
Then make sure you have a cool mist humidifier in her room. Turn it on before you plan to put her to bed so it is nice and humid when she is ready to sleep. I have an ultrasonic one (I think it was ~$30 at Target) I like it better because you don't have to worry about replacing or cleaning filters which get funky rather quickly.
And lastly you can use the saline nose drops to help loosen everything up. Be careful using the nasal aspirator (aka booger sucker ;) )Using it to often can make the nose inflamed and in turn make the situation first. Use the saline in the nose before using the aspirator. I hate using it and only do it when I feel I really have to.
Unfortunately stuffy noses in infants usually means a couple tough nights. Hope this helps-Good Luck!
Oh-I just saw someone recommended the car seat-that is also a really good idea. I found that very helpful too. But like the other mom said be sure buckle her in!. I left the straps a little looser so my kids move a little but they definitely need to be snapped in.