If your physician has asked you to take Vit D then you need to take Vit K2 (not K1), at least 100mcg with ~5000IU of Vit D. Long story short, Vit K2 tells your mobilized Calcium (by Vit D) where to go. Usually, Calcium supplementation is not required unless your osteoporosis is severe but Magnesium is required (I know, it doesn't sound right, but Vit D moves a lot of Calcium in the body).
I agree 100 percent but would like to add some caveats. Since so many people are on so many different meds you may need to consult with your doctor about
taking K2, especially those on blood thinners.
Calcium supplements alone are associated with calcified arteries and kidney stones and K2 (and perhaps magnesium too) is what removes the calcium from the soft tissues in the body and moves it to strengthen your bones.
Also make sure that the vitamin D you are taking is the natural form, D3. Artificial D2 has more side effects associated with it. Also 5000 IU of vit D3 is probably safe but you should get your blood levels of D3 to see exactly where you stand.