Maureen,

Look in your phone book under appliance repair parts. There will be store
that stock these elements. Give them a call. Before you call write down the
Brand and model Number so you can tell them. The people in these store are
usually very helpful. There are lot's of internet stores too.
Are you sure that the problem is in the element? A cheap way to check is
to swap the two large elements and see if the "broken" element still fails
to work in it's new position.

Dave M.