How is stress related to the hippocampus and amygdala?

After reading the web article on “Early life stress can leave lasting impacts on the brain”, please answer the following:

What is the main function of the hippocampus?
How is stress related to the hippocampus and amygdala?
The authors mention that unless we understand what part of the brain is affected, we wont be able to tailor something to do about it,. What type of therapy or treatment could you envision for a child with these experiences? Or an adult that had them and is now living with the long-term negative effects of a stressful childhood?