You can create a third widget area by putting this
PHP Code:
<tr>
<td id="top-widgets" colspan="<?php echo $cols; ?>">
<?php // 3rd Sidebar
if ( !function_exists('dynamic_sidebar') || !dynamic_sidebar(3) ) :
endif; ?>
</td>
</tr>
into header.php, before or after
PHP Code:
<tr>
<!-- Header -->
<td id="header" colspan="<?php echo $cols; ?>">
<?php bfa_header_config($bfa_ata_configure_header); ?>
</td>
<!-- / Header -->
</tr>
and put this
PHP Code:
register_sidebar(array(
'name'=>'Top Widgets',
'before_widget' => '<div id="%1$s" class="widget %2$s">',
'after_widget' => '</div>',
'before_title' => '',
'after_title' => '',
));
into functions.php after this
PHP Code:
register_sidebar(array(
'name'=>'Right Sidebar',
'before_widget' => '<div id="%1$s" class="widget %2$s">',
'after_widget' => '</div></div>',
'before_title' => '<div class="widget-title"><h3>',
'after_title' => '</h3></div><div class="widget-content">',
));
Then install this widget
http://forum.bytesforall.com/showthread.php?t=258 . Put your banner code(s) into (a) text widget(s) and put the text widget(s) into the newly created "Top Widgets" Sidebar. Then use the instructions in that thread to show/not show those text widgets based on Wordpress conditional tags as described in that thread, and more examples here
http://codex.wordpress.org/Conditional_Tags