You can translate the plugin just like any other WordPress plugin. Just use a translator tool (e.g. Poedit), open a file named woochimp.pot from /languages directory and translate the strings.
Save file to folder "/wp-content/languages/plugins/" with appending a language code at the end of file name, e.g. for German, you would have two files – woochimp-de_DE.po and woochimp-de_DE.mo.