Hi Okie. While I'm no expert myself and I'm sure there is probably someone here more qualified to answer this, I'll give it a shot.

Flea's like all other parasites become intolerant to main steam chemicals. (Frustrating I know)
Anyway try treating pups bedding with Eucalyptus products. Yard area with Agri-lime you get it at Live Stock Places or Nemitodes (it's a worm that eats flea eggs and lava) get it at Earthworm Farms. Flea bomb carpets and sprinkle with Eucalyptus Oil. Then feed pup Age-garlic Oil by putting drops in it's feed get at Health Food Stores. This may seem extreme but, necessary to take full care of the problem.

No! You can not use Advantage more than once a month, I'm under the belief that it can poison the dog.