Wordpress website design

I am using this theme in my wordpress site. This is my site so far. un-processed.com

http://www.dessign.net/simplegridtheme/

I need to have it set up so I can do posts (for some reason all my posts go to the about page).

This is what I need:
The posting feature to be fixed.
The images in the attached file are just placeholders.
My header images to be resized. I can upload the original image files for this.
Social networking additions - instagram, linked in, google plus
Mailing list function to work at bottom of site.

Thanks.