After searching I found a fix. Many thanks to those who suggests a fix stell and Peaches :-D
1. First Backup your blog to be on the safe side. This can be done using the export-backup function or the old backup method.
2. Backup blog Template using select-all-copy-paste from your Template Code box (Template---->Edit Html tab) to a Notepad file and save it on your disk.
3. Find your BlogID Number : This is essential as it will be used in the next step. To find it login at Blogger.com and click New Post button on Dashboard under the title of the blog you want to upgrade to Layouts. The Create Post page will open with a blank Post Editor. Copy the content of the address bar. It will look something like this :http://www.blogger.com/post-create.g?blogID=BIG_NUMBERCopy the BIG_NUMBER at the end of the address/URL.
4. Login at Blogger.com if you are not already logged in and open a new tab in your browser. Copy the URL below and paste in the address bar :http://www.blogger.com/customize-template-choose.g?blogID=BIG_NUMBER&templateName=MinimaReplace BIG_NUMBER with your BlogID Number you copied in Step 3 above. Hit Enter key on keyboard.If you have followed all steps correctly the Select New Template tab will open. Select your template and click the "Save Template" button.
NOTE : This is not same as picking another Classic template for your blog. The URL for that is :http://www.blogger.com/template-choose.g?blogID=BIG_NUMBERThe URL for picking a new Layout is :http://www.blogger.com/choosetemplate?blogID=BIG_NUMBEREnjoy!