How can I fix the blocks in center post for all courses in Moodle 2.3

I have added 4 blocks in course page at **center post** (Bottom portion of the page) region per particular subject. These 4 blocks are positioned at center post using `Pagelayout.css`. When I manually add them their position is correct (Using GUI i.e Add block). When I am changed/selected different subject (Course), then these blocks are appearing in **Side-pre** region. But I want to get these 4 blocks in **center post** irrespective of the subject. (i.e independent of the subject, these 4 blocks should be in **center post** region). I added the line: $CFG->defaultblocks_topics = 'news_items,search_forums,blog_recent,online_users'; in `moodle/config.php`. So I am getting these 4 blocks in all courses, but these are coming/appearing in **Side-pre**. So, how to get these 4 blocks in **center post** region and **Navigation block** should be at side-pre region only? Actually I want like ![enter image description here][1] But currently, these blocks appearing in `side-pre` region like ![enter image description here][2] How can I get blocks in center-post like in first image? [1]: https://i.sstatic.net/4pzVm.png [2]: https://i.sstatic.net/hXsKW.png