Flea bombs (need to get some myself too) set off in room with doors and widnows clsoed and no people or pets (or plants iirc!). Leave for hour or so then air room.
Have always worked for us. Except this latest time, so am about to re-bomb!
Also cat flea collar in hoover bag has been suggested to kill any you hoover up.
It will be some weeks before you stop finding them popping up as the sprays do not kill all stages of the flea's lifecycle and eggs can remain dormant in carpets for a long time. They hatch, triggered by m sensing movement nearby I think, and then will die a little while after they come into contact with the treatment you have applied to the carpet. You should find those you find later on are slow, easy to catch between your fingers and remove whereas you'd never normally be able to do that with a flea, it's because they are suffering the effect of the treatment you have applied.
There are sprays that deal with other stages of the life cycle than just the adult - your vet should have them, things like Indorex. Try using Frontline combo instead of the normal frontline as that contains an environmental treatment that the cat will spread about wherever he/she goes. Makes it a bit more effective than the frontline alone, though that is pretty good. Contact the manufacturers of the Frontline (Merial) if you feel the ones on your cat are still alive after 48hrs though as they have good product support.