If you value your cat at all you had best get to a vet as soon as possible. You will not be able to pull the kitten out and she will not be able to expel it on her own. If left in for many more hours she will become ,if not already, infected and die. The cat will require surgery and the kitten will have to be removed from inside. You might try and give the kittens to the other cat because they now are most likely orphans.
Bill
Bill