Look in your theme.html file and find your banner tag
<{$xoops_banner}>
replace it with...
<{foreach item=block from=$xoops_crblocks}><{include file="your_theme/theme_blockcenter_r.html"}><{/foreach}>
now in admin>blocks> use centre right block position to hold your required block. You may want to edit the template for the block to remove the block title and change any formatting. NOTE: This will only work of course if you are not already using your center right block for exixting content. Plus your block content should be sized to fit into your header without breaking it. You can use any blocks tag for this and move them to various positions on the page to suit your content.