You need to redownload your template file from themeforest. Log in there and then you click on downloads. You can download the newest version 1.1 then.
I suggest to use a ftp program to update your theme. Backup your theme folder (rename it or download it to your harddisk and delete the theme folder on your server afterwards). Then upload the new unzipped/unpacked theme files to your themes directory. If you made any css/php/js changes you need to modify the new theme files again. Please don’t use WordPress auto installer.