Fleas are absolutely awful. I'm so sorry. If she's an indoor cat, and she has fleas, there are very likely flea eggs in your house (especially in carpet or rugs)
We had an indoor cat who got fleas growing up, and we had to take drastic steps to rid the house of them
It's time consuming and stressful. It really stinks.
I'm not super familiar with Capstar, but it looks like it only kills the adult fleas that are on your cat, thus disrupting their life cycle and giving another product time to start working-- does that sound accurate?
Is she getting combed daily?
Have you treated your upholstery and rugs with anything?
Vacuuming and then emptying the canisters into plastic bags and taking them outside immediately?
Is using Advantage an option?