This question comes up every now and then.  So...

First, that's not the way RSS works exactly.  RSS feeds are shared by the newsource creator to include the information you get from the feed.  If you want to see 'whole story, you are given a link to follow.  That's the way it works, for DNN and other newsreaders.  You could write a screen scraper to 'get the whole story', but you would probably be violating copyrights.  Most newsfeed sources  provides usage information regarding their content, and provide the newsfeed as a service, but don't expect newsfeed sources to allow you to display their news without attribution or visiting their site for the whole story, otherwise, why would anyone share the news they pay reporters, photographers, and syndication services to create their content. 

If you want to display news locally, then provide you own content, or abide by the RSS methods that allow sharing of news headlines, and blurbs.  It's the way it works.