Thanks so much for your response.
I've located the section of code, from the header.php file that was in wp-content > themes > TheThemeI'mUsing. (I'm spelling that out as there are four header.php docs in my cP)
1) I'm assuming when you say "ad it in the div blogtitle", you mean add the image URL in the div blogtitle?
2) I'm not sure where in the div to add it I'm afraid. So I'm pasting the code here in the hope you could let me know:
<div id="blogtitle">"><?php echo bloginfo('name'); ?></div>
<div id="blogdescription"><?php echo bloginfo('description'); ?></div>
Thanks once again for sharing your knowledge, I really appreciate it