I Been Recently Diagnosed With MS, And I Been Prescribed

I been recently diagnosed with MS, and I been prescribed Plegridy 125mg every two week injection shot. I do follow up blood work every 3 month as well, my latest blood work showed Iron deficiency. I am also Vitamin D deficient. I wonder what is best form of Iron supplement and Vitamin D3 to take.
I am 51 year old female. White of the Eastern European decent. Not sure if this information makes any difference. thank you I advance for your reply.
Galina