I am a groomer. I would NEVER use flea shampoo on one of MY dogs. It dries out their skin and makes them itch worse than the fleas. You can cover her in dawn dishsoap and wrap in towel for about 15 min and then rinse, that should kill the fleas then shampoo with an oatmeal shampoo.
I do have to use frontline once in a while as I live in Texas and do have fleas sometimes. For a tiny dog I would use about 2 tenths of a cc on the back of her neck.
I can treat about 15 poodles with one LARGE tube of frontline. I never use the amount on the package, too broad a range in pounds.
Frontline's patent is up so there is now a generic Frontline at Walmart call "Pet Armour" , its not really much cheaper , but more available.
If you have just a couple of fleas, just bathe and pick them off. If you have a continual problem, I suggest Frontline. Advantage makes me ill for several hours if I use it. It goes into their nervous system. Frontline goes into their fatty tissue right under the skin.
hope this helps,
pam in TX