Place the login block to my own div sec

I'm not sure I understoond what you mean, but:

1) To place a certain block in a certain region: Assign the block to the appropriate region from http://yourwebsite/?q=admin/build/block
change 'yourwebsite' to your actuall website domain name

2) To place a certain region in a certain area on the page: In your theme, open page.tpl.php and put the region wherever you want it to appear, (i.e. type print $left in the appropriate place). You can check the region variable name from yourthemename.info. (In this example the region name is extracted from regions[left] = Left Sidebar).
change yourthemename to your actuall theme name.

3) To change the style of a certain block: View the source code of the page in which the block appears, and find out the block id, then open your css file and make a new entry with the name of the block. For example, to change the user id in Drupal.org front page, use this code:

#block-user-1 {
put whatever style you want here
}

I hope this helps.

hi use direct code in your page.tpl.php for display login box....inside your div