I am not sure what you by your “paid code”. In order to upgrade you must install/upload the theme file. Instructions are here, http://support.themely.com/knowledgebase/how-to-upgrade-integral-lite-free-to-pro-version/

The 2nd issue you mention is a hosting/server issue, this will assist you, http://support.themely.com/knowledgebase/upload-max-filesize/

Let me know if that helps.