My name is***** and I would like to help you and Zoe. You are doing a great job by keeping her on a covered heating pad and trying to get fluid into her. Ideally at this age, she should be seen by a veterinarian for a physical examination. It is unusual for adult cats to get pneumonia from being bathed and this suggests that perhaps there is something more serious going on that is suppressing her immune system. If you are unable to get her in to be seen, there are a few things you can attempt at home that may help.
Using the supplement Pedialyte will help to keep her hydrated- you can use a turkey baster or syringe to give her small amounts at a time. This can be warmed to keep her body temperature up (ensure you test it first on the palm of your hand before giving it to her to ensure it isn't hot).
You can use the children's medication Little Noses- 1-2 drops every 8 hours- to help her congestion. Ensure the product ONLY contains saline- no other medications should be in it.
Placing her in the shower after it is run on hot for a few minutes will allow the steam to help break her congestion.
Ensure she continues to eat- often cats that are sick can't smell their food
and stop eating- you can use non-onion based baby food (warmed), tuna water, and low sodium chicken broth to help stimulate her appetite. There is also a paste you can purchase called Nutri-cal that is a high calorie supplement.
If she has thick, colored mucous from her nose, begins coughing, is excessively lethargic, has pale gums, a distended abdomen, or is not eating, she should be seen.
I hope this information helps. Please let me know if you need anything else at all.