At present I would reccomend nothing in the way of supplements until you have had your Doctor/Endo blood test you for deficiencies.
Ask for your Vitamin D, B12, Calcium, Selenium, Magnesium and Zinc to be checked.
It is unwise to take any supplements until you have the ok from your Doctor as this could aggravate the RAI treatment.
I was the same as you (had RAI June 2008) and had problems with healing.
Get your Doctor to check your bloods.
Hope that helps
Graves is an autoimine disorder so you dont want to be doing anything right now to boost your immune system,.