Google News only shows 30 days of news, and once that 30-day window has passed, your news gets dropped into the archives. To access any older news content, you must use Google News Archive Search. According to the folks at Google, if your news stories are older than 30 days, they don't automatically get archived. In fact, you need to request that Google archive the stories for you. Should you want to be included in the archive search, you need to follow the instructions on this form and submit the proper material to Google for consideration.
Source:→ Search Engine Roundtable