will a new cat helps my cats?

I have two female cats; both under 2 yrs old. One runs the house; the other has always been hiding under the bed (we have two labs, but that doesnt seem to be an issue). The cats do not get along - they used to sleep together, but no longer do. I am considering getting a male kitten to see if it will "even out" the tension between them. Im not considering this just to apease the cats, but I really am feeling that there is a void and would like another cat. I am not sure if this would help or hurt. Our under the bed cat doesnt come out until night to eat/drink and get her nightly petting when we go to bed, but I feel that she is miserable and would be happier in some old ladies house without any other animal action, or people action. I am at a loss with her and feel so bad that she won't get along with other animals, or even come to us for affection during the day. Help!