My kitten won't leave my older cat alone. Any suggestions?

I adopted an adult cat from Adopt an Angel two years ago. At the time she was one and now she is 3. She is fixed and a little on the heavy side. She doesn't like being held or laying in my lap, but she does play by herself and would come and talk to me when I would get home from work. She is also wary of strangers. About a month ago I brought home a kitten that was a stray and she doesn't like him. He is anywhere from 3 to 5 months and he drives her crazy. He wants to play with her, but she wants to lay and be quite. How can I get them to get along? I feel bad for her because I brought him home to give him a home and to keep her company. My stepmother as my kitten's sister and an older cat too, but they play together and Tom usually puts Alice in her place when he's had enough. Yet with Autumn and Ken he runs after her and she hisses, growls, and strikes out at him with little avail because her keeps coming after her anyway. It's like he doesn't seem to understand that she doesn't want to play, etc. Also when I get him fixed will he calm down and leave her be? I'd hate to think they could never get along.