you should always update to the latest. AFTER you back up.
install the db-backup plugin, and the auto-upgrade plugin to make it easy. (the auto-upgrade does make backups but I like knowing I did it myself with the db-backup)
DB backup http://wordpress.org/extend/plugins/wp-db-backup/
That most likely won't solve your formatting problem, but should be done - a side issue, actually
The main issue is in WP is that you are not dealing with whole pages of HTML but with page fragments, which WP assembles into a whole page each time a page is displayed.
The header is in one PHP file. The sidebar(s) in another (or two others). The footer in another. And the main content is held in a series of PHP pages. Generally only one is used per page, but WHICH one varies depending on a number of possibilities - the logic of which one is all contained with WP's core code. To become an intelligent WP user requires, over time, that you learn what is called in and when.
When you see something like you are experiencing, that is a tipoff that a different page is being called in on your mission statement page. Or else, that different logic is being applied from the page header (such as a different or additional style sheet applied to that page).
I didn't look at this before, but you only have one PAGE, the mission statement, on your blog. All the rest are blog posts, being presented on the home page, or in categories or archives. That means that the page.php file is called in for the mission statement, which contains different code. You will find the problem is with a misplaced closing div tag
</div> as i said before.
Now I see your home page has the sidebar below the posts. This is also due to either a misplaced closing div tag in the index.php file, or else this can happen if the stated width of the contents area plus the sidebar area combined (including padding and margins) is wider than the container in which they are trying to fit.
Did you save a copy of your theme before you started making changes to it? You might want to save what you have now and then restore back to the most recent version, where only the mission statement was messed up, and proceed from there