How to insert a lot of emails at e-Newsletter?

Hi, I receive a lot of emails through gmail and they come with this format:
<xxx@xxx.com>, xxx <xx@xxx.inf.br>, "xx@xxx.com.br" <dxxx@xxx.com.br>, "xxx@xxx.com.br" <xxx@xxx.com.br>

How can I get this and put it at e-newsletter? I know there is a way through Excel, but I would still need to waste my time dividing them. So, do I really need to format it one by one for inserting it at your plugin? Thank you.