The calcium is the single most important thing to do. Too much is better than too little. If this form is calcium carbonate, it will take a little longer to work, so doubling or tripling the dose is okay. Calcium has to be given in large doses for an extended period to be toxic to the kidneys. Short duration is not a problem if you happen to give too much.
Be sure to provide the sugar water since she will be thirsty.
Oh, no! I just posted as you did.
Save all these instructions in case this happens again to another hen. The first sign of egg binding is a hen standing or sitting motionless with her tail held low and flat. At that first sign, give a full calcium citrate tablet. I keep a bottle in my run to have handy in emergencies such as this. Time is of the essence in treating egg binding.
I'm so sorry you lost her.