Why is my guinea pig so loud/annoying?

My guinea pig is almost 3 years old, and about a year ago got too big for her cage, so we had to get her a big one. unfortunately, the bars are movable, and she learned when she's bored or hungry she'll rattle the bars until her needs are met. She'll also squeak as soon as a stranger comes in. And when you try to pet her, or take her outside or even re-fill her bowl, she'll hide in her house, then go right back to squeaking, even if there is food. I don't know know what to do for her. Giving her away is not an option here. What can i get for her or feed her, or anything that will keep her quiet?