Can you do without milk and dairy products and still have sufficient calcium intake?

A hard thing to do, unless you completely change your eating habits. Dairy foods are an essential source of calcium, in both quantity and quality. Dairy calcium is regarded as the "reference" calcium.

A glass of milk (250 ml) provides 300 mg of calcium. The same quantity is contained in 2 yoghurts, 30 g of Comté [hard cheese], 80 g of Camembert [soft cheese], 300 g of fromage blanc curds. Calcium in milk and dairy products is recognised as being more bioavailable than calcium from plant sources. Fruit and vegetables, as well as certain (calcium-rich) mineral waters, can provide additional sources of this mineral.

Source: IFN