@discographer-- Oh yea, the lungs hate cold air. I'm sure sitting in the cold made things worse for her. Make sure that her house is warm. She needs to keep herself warm and if she has a humidifier that she can keep in her bedroom, that will help a lot. Lungs love warm, humid air and it will also help her breathe better.
Aside from this, if she's taking her antibiotics, she should start feeling better soon. She needs to drink a lot of water. Water is a great expectorant and not getting enough will slow down recovery. Soup is a great idea. If she doesn't have diabetes, fruits and fruit juice will also help. You can also make some tea for her. The more fluids, the better!
If she gets worse instead of better though, please take her to the hospital. Pneumonia can be very dangerous for the elderly. She may need an IV serum or stronger antibiotics if things are getting worse. Please keep an eye out on her, you're doing a wonderful thing.