The more information you give the easier it is to help. You haven't given much. Relevant details would include whether or not you have other animals (mammals) in the house and how long ago the cat was in your house.
It's probably cat fleas. Assuming you have no dogs or especially cats in the house, your flea problem will only be temporary. Worst case scenario some gravid fleas will have jumped off the cat and laid eggs. They may be able to hatch and grow up eating dander or something similar, this will allow them to become adults, but without an appropriate host they shouldn't be able to complete the life cycle so your problem should end there.
I don't know what stage you're at or what your situation is, so I can't really advise further. There are various poisons and non chemical options such as diatomaceous earth, but I'd need more details to know which I'd want to suggest.
Good luck.