What is maximum number of cc's anyone can get expanded? How many cc's to achieve a D cup?

This is a question your surgeon can best answer as he is seeing you and taking care of you. If he has concerns about healing with further fill then that is worth listening to. He may be concerned about wound healing and loss of the expander to exposure. A history of radiation treatment would particularly make it risky to fill beyond a certain amount. If you doubt him, then it may be worth seeking a second opinion. Or you may want to discuss with your surgeon how you can achieve the size you want, possibly with further tissue brought into the breast.

Thank you for the question. There is no accurate correlation between size of breast implant used and cup size achieved.
Generally speaking, the best online advice I can give to ladies who are considering  breast augmentation surgery ( regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully.  Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you're looking for. Ask to see lots of examples of his/her work.
2. Have a full discussion and communication regarding your desired goals  with your plastic surgeon. This communication will be critical in determining  breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as  “natural” or "C or D cup”  etc means different things to different people and therefore prove unhelpful.
 Also, as you know, cup size varies depending on him who makes the bra; therefore, discussing desired cup  size may also be inaccurate.
3.  Once you feel you have communicated your goals clearly,  allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals.  Again, in my practice, this decision is usually made during surgery. I generally select appropriate breast implant size/profile after the use of temporary intraoperative sizers and viewing the patient's chest in the upright and supine positions.
I hope this (and the attached link) helps.

Pictures would help. Your height and weight make a big difference.  You can continue to expand as long as your skin is OK with it. It does get thinner the more you expand however. A D cup in reconstruction is usually more than 500 though.