You can buy a 'flea bomb'.
I have used them and they do work. You need to remove all plants and livestock so not a lot of use if you have a fish tank.
Try your pet supply shop.
Your vet is bound to sell products that will sort out your problem. In the past we have used something called Nuvan Top. Using Frontline or something similar on your cat once a month will prevent the cat getting the fleas in the first place. It is a little 'tube' which you empty at the base of the cat's skull. Again your vet will be able to provide this.