Well, I would include some of the following:
-Comfy PJ's & plush socks
-nail polish
-Sodoku puzzles with a sharpened pencil (or 2)
-local daily newspaper
-paperback novel by an author she likes (or style of novel she likes)
-a current baby magazine
-CDs (does she have a CDplayer/radio in her room)
-TV guide
-favorite candy bar and snacks
-Gum
-A journal to write in
-Stationary (or Thank you cards) and stamps
-If she has a portable DVD player... bring some movies she hasn't seen, or OLD movies that are classics (Gone With the Wind, Casablanca, The Birds, The Godfather) or a TV series on DVD- something like "Frazier" that is funny but not "brainless"
-If she knows how, some sort of needlework.. if she doesn't, find a small kit that she might be interested in learning how to do.. (They sell kits for cross-stitch that include the thread and everything in the bag), or even a latch-hook kit would help pass the time.
- watercolor materials: tube paint (don't need but a few basic colors) and 2 brushes-1 small, and 1 med-large, a pad of watercolor paper, and a white plastic palette - you can get all this at Michael's for under about $30 -- if you look at the discount racks at a bookstore, you might can find a How-to book pretty cheaply.. She doesn't need an easel, it's done flat (on her food tray is fine)...
P.S.
Others have recommended the DS Lite (Nintendo) and it is great! (I have one too), but it is pricey for a "pick me up". The games are an additional cost @ $20-$35 each, but it does come with its own charger and it lasts a pretty long time in between charges, too. If it is in your budget, this is a super choice.