_There are plenty of foods other than milk that contain calcium.

Here are some foods that contain high amounts of quality calcium:
almonds, broccoli (miracle vegetable!), oranges, figs, amaranth, quinoa, seseame seeds (probably natures richest source of calcium - try making your own hummus with loads of garlic and himalayan salt yum!), and who can forget green leafy vegetables, heavily advocated by Dr.Mercola for good reason, these contain vitamin K aswell, to "glue" the calcium into your bones.

_If you are a low carb eater, then the oranges and figs would probably not be a good choice, although the others should be suitable.

_You should heavily consider adding quinoa and amaranth to your diet, as they are a powerhouse of nutrients. Loaded with minerals, really high amounts of magnesium and phosphorous as well, which are both vital to bone health.
They are around 30-40% carbs, but when eaten with good fat such as olive oil or an avocado will be very slow release.

_If you are keen to supplement, then coral calcium is a must. The natural porous structure ensures excellent absorbtion. It also contains many mineral co-factors. I have had great success with coral calcium. It is tasteless, and mixes really well into food. I put it in porridge, and soup, well it goes in almost anything.

_Some Italian mineral waters have loads of calcium eg. Fararelle which has 380mg calc/L. So a litre a day would be a significant amount of calcium. Best to take at meal time though, to ensure effective absorbtion.

_I hope that this information will be useful to you, at least you can research and experiment with a few of these and see what works for you.
Remember almost all foods will have a small amount of calcium, so with a varied diet, foods that you would not expect will add probably around 200mg or so of calcium that you thought you were not getting. ie. nuts, beans, fruit & veg.

Do some of your own research, as I have likely not included some foods that are really high in calcium that I dont know about!

And don't forget, your body will make incredibly efficient use of  calcium if you get regular intense excercise & weights, get enough vitamin D, healthy intestinal flora, have saturated fats (coconut oil), and the other minerals needed to make strong bones.

Look up xylitol too, (it enhances calcium absorbtion).
Hormones will greatly impact bone formation aswell.
That's enough from me! I could go on forever! Sorry, but it is really a very complex item to discuss, with so many things involved.
Mercola.com is a very thorough site, so I feel I should give a very thorough comment! All angles covered!

I have been using coral calcium in a powder form for about 3 months now... No digestion problems... I use it every day with my shake.. no milk... rice milk for me