From Food Allergy Groups of Wisconsin's next Newsletter - from our dietican -

One way to get calcium is to make enriched broth from meat bones.  To make
the broth take chicken, turkey, pork or fish bones and boil in several cups
of water with 2 or 3 tablespoons of apple cider vinegar (white vinegar works
too, but for those avoiding wheat or celiac would use cider vinegar) have
been added.  Boil for 30-60 minutes or until vinegar flavor has evaporated.
 One tablespoon of broth may contain as much as 100 mg of calicium.

1 cup of brocoli  equals 100 mg if cooked, and 50 mg of calicum if raw.
1 cup of cow milk is 300 mg of calcium.

Our newsletter is $5 for 4 issues.  So far we have about 50 families in
Wisconsin plus others throughout the US.  Its an open forum so people can
share stories and recipes and quick tips.   If you would like the upcoming
issue, just let me know your mailing address.   We have a few support groups
around the state that meet.   We don't share names with anyone.