If I were you I'd forget the whole Xmap sitemap concept alltogether. And do it manually. A weekly submit is ideal, but submits are tantamount the updates you make in the site. So, if you didn't update anything that week, no point on resubmitting.
Go here http://www.xml-sitemaps.com/ and build one there easy. Download the .xml file and upload it to your server root directory so that it lives in the internet. Make sure you have it in the main root. The more you nest it, the harder for Google spider to find it in a crawl.
Make sure it work by simply going to your browser and plugging www.domain.com/sitemap.xml.
Then you'll know you did it right. Then go to Google Webmasters and submit it and index it.
Before you do all that. My advise is to run your site through http://www.brokenlinkcheck.com/broken-links.php#status and check for broken links. fix them and then build your sitemap.
This sounds complicated but its not. Of course there are agencies that do this for you for a small cost, but if you do it yourself you'll save the money