WordPress Local And Live Site

I have a local WordPress install that I am using to test a new theme out. When I initial set up the local site I was able to import my database and media content. However that was a few months ago. Since then my live site has new content that I need to have in my local site.

How do I go about updating my local install with the latest content? Will I need to import the database again or just somehow export and import my latest posts? Any help or suggestions would be appreciated.