I recommend taking her to a trainer/behaviorist. Maybe your vet or groomer can recommend someone. If the behavior is new or sudden, could she be sick? Maybe the vet can help.
It sounds like this is territory agression, not fear agression, so you might be able to have fix the problem by asserting your "alpha" role in the family pack. If she growls and bares her teeth at you over a meal, that is a dominance challenge. www.doggiedoor.com has some good behavior advice for correcting agression without negative reinforcement.
Meanwhile, take precautions to keep her away from the kitten and kids who might get hurt suddenly.
Good luck!