Many vegetables and other foods contain easily absorbed calcium. Broccoli, kale, bok choy, cabbage, mustard and turnip greens provide high levels of calcium plus a host of nutrients and phyto-nutrients. Other good non-dairy sources of calcium include dried figs,almonds, sardines, and salmon.
To maximize absorption, calcium needs Vitamin D. ALthough your body can make vitamin D from UVB rays while in the sunlight, it's an unreliable source. Include regular doses of salmon, mackerel, tuna, sardines, and egg yolks in your diet to obtain vitamin D through food.
Presently in the US, dietary recommendations are 400 IU of vit D per day in adults ages 50-70 and 600 IU for those over 70. Some health experts find these number on the low end. Dr. Christiane Northrup, makes a case for higher doses of Vitamin D for women in her article Protect Your Breasts with Vitamin D. This article sheds light on sun exposure, Vitamin D's role in bone health, and some telling results from a 4 year study.
Another great reason to eat your veggies!