Cusomized theme issue

I have a customization/theme problem. I have my WordPress customized into my website on my blog page. My blog url is always mywebsite.com/blog.html no matter which post I click on. The problem with this, is that I installed All in One SEO, but the unique meta-tages don’t show on any of my posts.

When I preview my posts from WordPress admin panel, the url is mywebsite.com/wordpress/?p=xxx, and I do have the unique meta-tags. I’m guessing I need to modify something in my theme index.php, to make it call the posts differently, so that it reflects the plugin? But I don’t know what or how to. I’d appreciate any help.