Sorry, this is outside the scope of Q2A and is not going to make it into Q2A core. However there are some possible solutions:
1. Use Wordpress as the blog, and use Q2A's built in WP integration.
2. Set up a second Q2A instance to use as your blog, and link the user accounts to your first (Q&A) instance. You can set yourself as an admin to be the only one allowed to "ask questions", and those questions would serve as blog posts. You could let answers serve as "comments" on the blog. This would require a lot of work, especially with theming, but it's possible.
3. Just allow users to post whatever they like on your Q2A site, whether it is questions or answers.