75% of my site is missing and I can not login to admin

[ericareid]

Before I purchase a new theme, I would just like to get an idea on how and why after upgrading to Wordpress 2.6.2, that my entire site has been screwed. I am unable to access the admin, it says "Your WordPress database is out-of-date, and must be upgraded before you can continue. The upgrade process may take a while, so please be patient."
see here:

I press the upgrade button, and nothing happens. I was even told to change a code in the myphp for "db-content" on my server, did that, and nothing changed.

Also my site is not fully restored. 75% of it is missing. How can I get my site and admin access back. Can someone help?

My site is http

Thanks for your help!