The file to edit is located at themes/dust-317/left-sidebar.php of your installation.
Line 11 of assigns the flickr user id (this is NOT the same thing as your flickr login id, see below). Replace the string 75017260@N00 with your own string.
You can find the string you want by logging into your flickr account, clicking on the link that says “you” or “your photos”, and then looking at the address line of the URL: www.flickr.com/photos/”yourStringIsHere”
my string is 22879692@N04