lovebird lovers!! help!

[BeeBee]

Okay. Here's my semi-quick intro:
I wanted a lovebird, very badly. My parents said no, they're too loud. However, my younger sister wanted a lovebird and formerly had budgies who she loved so I suppose that made her a better candidate for a bird, in my parents' minds. I got her a little young lovebird, hand-raised and precious, for her birthday on March 3. She almost cried because she was so happy, but now...

Scout, her bird, has been moved out into the family room because my sister gets annoyed by her in the morning. She gets the bird out for about fifteen minutes every three days, and my mom changes the cage and toys regularly with complaint. I always offer to take the bird to my room and take care of it myself since she's not getting much attention, but that's when my sister chimes in, "NOOO IT IS MY BIRD!"

On occasion I will try to handle Scout, but she's grown aggressive. Probably from being so lonely. She bites everyone now, though my sister claims she doesn't bite her. How much interaction do lovebirds require? And does anyone have any helpful re-taming tips?

I feel so horrible for Scout...