Playfelt- I was going to try the booster seat at my breakfast bar today instead of the tray and see how it goes, but honestly I don't think it will work. This child is very stubborn and gets her way at home. I do only give her one or two pieces of food due to the throwing.
Today at drop off, mom informed me they had a "picnic" last night for dinner and her daughter ate way more than she ever has (I wonder why). I told her that it was because she got her own way and that I was going to continue with the booster.
There is no way this mother is going to wean her off a bottle right now. I think she will be on one for awhile yet but I suggested to her mom to bring in soy milk for her daughter, but we will see if she does.

On a side note, at what age do you allow kids to sit at the table to eat (not in a booster etc)?

Thanks for all your advice.