You can buy a bag of food grade diatomaceous earth and spread it around where she sleeps. This natural productt will choke the fleas an is perfectly safe for your cat. However, do not use it near fish because it wil kill them as well. You can get it at a gaden supply or health food store or online.
http://www.internet-grocer.net/diatome.htm
Please let me know if you still have questions or want to discuss this further.
Feline Healthcare Expert
Expert in feline health and behavior. 20 years experience with cats.