How should we contain black mold that is growing in our house?

Find the source. Try and find the source first, and fix that problem first. There are also companies which will come and evaluate your home and help you take care of the problem.
Eliminate the water. Mold growth is a sign of water intrusion. You need to first identify the source of the moisture and fix the problem. Then you can remove the mold by removing porous surfaces such as drywall and carpets, and washing nonporous surfaces with a bleach solution.