There are three ways to update your existing install of Business Pro to the latest version. You can always get access to the latest version of the zip from your account page.
The fastest and easiest way is via our Update API. Simply visit the Updates link in the sidebar when logged into WP-Admin on your site and scroll down to the themes section. Simply check off the box next to Business Pro and press Update Themes.
If you have FTP access to your server, simply upload the new businuesspro folder to the wp-content/themes directory, overwriting the old files with the new ones.
Or, if you would rather use the theme installer in WP-Admin, simply activate the default theme (2011), delete the old version of Business Pro, and then install the new zip as you normally would.
You do not have to worry about your settings being lost as they are stored to the database.
Did this documentation not suffice? Have more questions? Please post a support topic in the forum. http://cyberchimps.com/forum/pro/business-pro/