Ok look in your skin1 directory and find head.tpl. Find this line near the top.
<img src="{$ImagesDir}/logo.gif" alt="Affordable Imprint" />
Either change the logo.gif to whatever your file name is, and upload the new head.tpl to the skin1 directory.
or rename your file to logo.gif and upload it to the images directory in skin1 directory.
Make sure you choose replace the file when you upload and back up before you make any changes.