I'm really worried that the time in the hospital is going to slow her development. There just isn't a way to get her the level of mental stimulation she needs while she's in there.
Don't worry. My 6-year-old son has been hospitalized a LOT, including two open-heart surgeries and seven angioplasties to correct a congenital heart defect, and had one stint at Boston Children's that lasted 6 1/2 weeks last January. And his time in the hospital has not set him back in the slightest. Kids are remarkably resilient. As long as one or both of you can be there for her and give her as much normalcy as possible, she'll be OK.
Her restlessness may also be her way of dealing with the unfamiliar/scary situation emotionally. But like someone else said, it's a good sign--if she were not recovering, she wouldn't have the energy to do anything but lie there. Just keep her away from those "biohazard" containers (my son thought the red trash cans were SO interesting...)
Is she old enough to be interested in videos and such? You might be able to borrow one of those portable DVD players from a friend, or play some favorites from home on the hospital set if it has a VCR (lots do). We occasionally brought a CD player and some small speakers to play familiar music for him as well.