Regards Iron, I consider anemia to be, usuallly a vit C defiency.
Another factor is llow acid stomach (that's 95% of the population). Most people are low in vit C and it is needed for iron absorbtion. There a plenty of vegan sources of iron: Apricots, parsley (also high in Vt C), pine nuts, sunflower and pumkin seeds, wheat germ and whole wheat.
To get iron levels up take a good dose, 4 to 5 grams a day split into smaller doses every few hours and eat heaps of the above foods especially whole grains.
Most people's problems stem from the refined foods they eat.
By the way for Vit D explaination -
http://www.alnaturalhealth.com/index.php?option=com_content&view=article&id=85:vitamin-d--the-sunlight-hormone&catid=39:vitamins-and-minerals&Itemid=71
Iron: have a look at iron facts at
http://www.barbhealth.com/articles.html
What you need in a Vitamin C supplement :
http://www.alnaturalhealth.com/index.php?option=com_content&view=category&layout=blog&id=39&Itemid=71&limitstart=5 
