I am unaware of anything like that.
Perhaps it's an idea to make use of RSS feeds. Otherwise I wouldn't see a possibility to actually grab those posts because your application would in that case need access to the database.
However, this is not the place to discuss those kind of things. We can only provide support to phpBB and not to other products because we usually simple just don't have the knowledge for this. It might be an idea to ask for support on a PHP related board that can assist you in that.
Good luck with your project, but I will have to close this topic now.