Buying a domain for a wordpress.com site will not allow you to use AdSEnse on the site. WordPress doesn’t allow it on their free hosted sites. You would need to purchase a business or e-commerce hosting account from wordpress to use AdSense.
Advertising through third-party ad networks like Google AdSense, OpenX, Lijit, BuySellAds, and Vibrant Media, or selling advertising space on your site, is only permitted on sites that have the WordPress.com Business and eCommerce Plans.
Even if you could afford to do that, your site currently has insufficient content for AdSense, and is not written very well in English, so it’s doubtful AdSense would approve it.