to up[date power store 4.1 to 4.5 you need to copy all of the power store php files and folders over your live site files and folders. copy the install/webassist folder over the webassist folder at the root of your live site, then run the sql script in the install/scripts folder for your update path.
you do not need to run the installer.
once the files are updated, the products insert and update page should have an SEO tab to enter product specific meta tags.