Go to your profile page, and near the top in the vicinity of your avatar, click on "Edit my profile". When you get to that page, click on "My Account Settings". In the top section of that page on the right, you'll find your e mail address. You can type in your new address, and then make sure you click "Save Changes" That's all there is to it.
So simple, Just go to your edit profile>My Account Setting. Here is everything that you want to change about you. You can also go to Edit My Blurtit and change accordingly.
Just login in and add your e-mail address with you avatar name and password.