Hello, Kortney and welcome!My name is XXXXX XXXXX it will be my pleasure to assist you and Dixie today.Bless you for taking her in! You saved a feline life! : )From your description, it sounds like Dixie has, or is beginning, an upper respiratory infection. Although this condition is viral (like the human cold), there can be bacterial elements and the vet may prescribe an antibiotic to prevent bacterial infections if they are not already present. The yellow color of the mucus may indicate bacterial infection.For the moment, you can use a humidifier in any rooms she spends time in and also, try some plain infant saline nose drops to help clear her nose. One drop in each nostril once a day, until you can have her evaluated by a vet, would be good. If she fights you on this, don't continue. Since you just took her in, it would be best to have her seen by the vet in person, as soon as you can, to make sure she's healthy in all respects (of course, except for the runny nose right now) and she might be due for vaccinations. The vet will also be able to tell you her approximate age. I hope all will be well with Dixie!