It is difficult when a new kitten is introduced to the mix. First, you should get them fixed if they aren't already because their hormones can cause them to fight each other. Make sure you give the cats equal time in your room and the home so they can both feel at home. To do this you can switch who is where, as well as the bowls they eat out of and the litter boxes they use. This will get them used to each other's scent making the switch easier. Also, if you must leave them alone, be sure to put the kitten in a room by herself for her safety and to show your cat that you acknowledge her as the first cat in the house. As for the cat sleeping elsewhere, it could simply be that she feels you have abandoned her for the kitten because the kitten now sleeps with you. You might want to get the kitten a bed in the living room and continue to bring your cat into the room with you. When you play with the kitten, be sure you play with your older cat too. This will show both of them that they are special and will wear them out.