Sure thing, for right now I would suggest just not updating to 2.0 just yet anyway.
Typically however, you updated in the exact same way you first installed the theme. You download the files from your Downloads on themeforest, then unzip that big file so that you have the folder with the license, version and other files. There will also be the replete.zip file which is the actual theme.
You just choose to install the theme from the wordpress admin just like you did the first time and will overwrite the current them. If it isn't able to, the permissions on your server are set in such a way that overwriting folders is not allowed from within wordpress. You can either ask your host to change it for you, to direct you in changing it or just update the theme via FTP.
For FTP, you unzip the theme folder so that its the replete folder with the theme files inside it. There will probably also be an OSX folder that can be deleted as it just contains information for Macs and isn't needed on the server. You then connect to the server via FTP, navigate to your themes folder and drag and drop the updated replete folder on top of the replete theme folder on your server.
You only need to make backups if you edited the actual theme files themselves.