To check the version number of a theme, take a look at the top of the style.css file. You can either open this file up from your computer directly, or you can open it in the WordPress editor and choose the style.css file from there.
1.1 is the latest version at the moment, but I do plan to have a new updated version of this in the near future. If you don’t make any edits to the theme files directly then you’ll be able to update to it by simply deleting the old version and uploading the new version.