Yeah brocolli is a great source

yum.
Sesame seeds are meant to be very rich in cacium as well as ya green leafies.
If you fancy it you could also try Nettle tea, it may not be the tastiest of herbal teas but it is verrrry rich in minerals, particularly calcium and magnesium. It's basically like a multi vitamin in herb form! A really amazing plant.
You would want to be having around 4 cups a day (it seems a lot I know!) and best to get it from a source other than supermarket if ya can because the herbal teas sold there don't have much medicinal value.