The company's shares rose 2.8 percent to $228.44 in late afternoon trading on the Nasdaq.
Tesla will demonstrate the enhanced range for the new Roadster in a drive from San Francisco to Los Angeles in the early weeks of 2015, the company said in a blog post.
The current Roadsters can travel up to about 245 miles on a single charge.
Tesla had discontinued the production of Roadster, its first car, three years ago to focus on its 'Model S' sedan.
The company launched the Roadster in 2008 and sold about 2,500 units until January 2012.
Tesla's announcement hints at plans to use more advanced battery packs in Model S sedans and the upcoming sports utility vehicle 'Model X' and the smaller 'Model 3' car, Stifel Nicolaus and Co analyst James Albertine wrote in a note.
Tesla is expected to launch the Model X in 2015 and the Model 3 in 2017.