[Theme: Infoway] Newbie, Need some formatting help

Hi all. This is my first time designing a website and I’m kind of learning by trial and error. I have a few issues:
1. I’d like to center my header logo. Can’t for the life of me figure out where the code to do so is located in the header php.
2.I’d like to center the stuff on my contact form page, or be able to add a sidebar..either would work.

here’s my site:
constantlyalice.com

Thanks for helping!
Best,
Danielle