Women and calcium suppliments - how much and what kind?

I know calcium is vital to women's health but I'm a bit confused as to what kind of calcium suppliment I should take, since there are different kinds. There is "chelated calcium" and "elemental calcium" and others....and I have heard mentioned that if you don't take it with Vitamin D that it's not as good or as well absorbed.

I eat veggies like brocoli and take dairy like yogurts, as well as other calcium rich foods but feel I could do with a suppliment too especially as I am not much of a milk drinker.

I am in my 30s. What should I be taking with regard to a suppliment and how much?

Thanks!