fleas are tough! The more an animal has, the harder they are to get rid of (Am not sure of the exact reason, it is just a fact I learned from pet grooming.)
If affordable, proffessional extermination and flea bathing for all animals in the house is the best.
If that is too cost prohibitive, an appropriate number of flea foggers (and this depends on the size of your house) is more effective than sprays, because it penetrates everywhere.
Always have the pet(s) bathed at the SAME time as the home treatment, not one day before or one day after. Remember it only takes 1 live pregnant female to jump from pet to carpet or carpet to pet, to start it all over.
If the animal goes in the car, spray out your car also. This is one area I think a lot of people forget. Remember again, all it takes is one flea to jump off the pet into the car and then on to you or back on the pet.
Now, keeping in mind the life cycle of the flea, in 7 to 10 days, eggs will hatch. Most products do not kill eggs and they will be in the environment, not on the pet. So a second fogging may be in order.
Good luck.