
Search for the code with id='header' in the code section of your blog without expanding widget templates.The block of code looks like this.
<div id='header-wrapper'>
<b:section class='header' id='header' maxwidgets='1' showaddelement='no'>
<b:widget id='Header1' locked='true' title='Bloganol Sample Blog (Header)' type='Header'/>
</b:section>
</div>
Now change showaddelement='no' to showaddelement='Yes' and maxwidgets='5' like below.Here maxwidgets='5' means you can add maximum 5 widgets in your header section.
<div id='header-wrapper'>
<b:section class='header' id='header' maxwidgets='5' showaddelement='yes'>
<b:widget id='Header1' locked='true' title='Bloganol Sample Blog (Header)' type='Header'/>
</b:section>
</div>
After you finish this save your Template.Here are the snapshots related to this hack.
Before:

After:

