How do I get my uncles dog under control?

Recently my uncle had to move in with his 12 year old dog. She is still extremely energetic and most people even think she is a puppy still. I have known her ever since he got her and she has always been insane. She is socialized and acts the same way with other dogs, strangers, and people she knows. She looks nice, wags her tail, but you just touch her and she growls, or barks. She nips very often, she has never drawn blood, she just gets annoyed. She is extremely temperamental and has now attacked every dog in the house (my pit bull, my mom's 2 shih tzus.) what seems like randomly. And also my cat. I can't put her outside for long seeing as we live in Florida and it is too hot for her winter coat. She has never shown any sign of affection towards anyone of anything. Not even her owner. She even did this to the dog she had lived with her whole life but it died last year. I am the only one in the house not afraid to push her down onto her side when she snaps, and now I'm the only person that she doesn't stare at. She thinks she is dominant over everything, and she even barks at me when I am making her food because she wants it faster. I have handled a lot of dogs, but I am at my wits end with this one. I am tired of getting bit when I try to pet her, and growled and barked at in my own house by a dog who thinks she is princess of the dog world. How do I get this dog under control now.