8 and 4 Year Old Out of Control

My 8 year old and my 4 year old are uncontrollable. They don't listen to me and when I talk to them they think it is a joke. I take away privelages and things they really like to do and still they don't respect me. My 4 year old smacks my 4 month old baby and tortures her to where the baby gets scared of her. I don't know what else to do. I cannot take or go anywhere with them because when I do they act out and everybody looks at me like I am a bad mother. I love my kids but they are driving me to where I feel like I am gonna have a nervous breakdown. Whenever I discipline them they say I don't love them. What do i do to have them respect and listen to me?

[margypops]

The baby of course should be protected form being hit by the 4 year old, perhaps she has learned it from the 9 year old.You have to be firm and consistent with punishments .the 4 year old is young enough to have time outs. If they know you dont mean it they will continue to misbehave. How long do you take privileges away for ?