If your cat has fleas, but you have not noticed fleas elsewhere, it is probably not necessary to fleabomb your house. Vacuuming very frequently,(including under the couch cushions and under the couch itself), disposing of the used vacuum bag as soon as you are done (fleas can live in the vacuum bag); washing all bedding- yours and the cats frequently in hot water; and of course, treating the cat with a vet approved flea treatment will usually suffice.
Do not use over the counter flea products on your cat. Some cats have died or become seriously ill from them. Get Frontline or Advantage from the vet.
If you feel your house is infested and decide to do the bombs, board the cat somewhere for the day or longer until the fumes die down. It is poison, after all. Don't forget to wash all surfaces afterwards to get the poison off (counter tops, dresser tops, light swithes, window sills where the cat will sit, etc.)
You likely carried the fleas into your apartment on your shoes or pant legs. They hitch rides on people.