In this order:
Open
WP Control Panel->Widgets and drop the widget into the sidebar you want it to appear in.
Edit the widget text to put in the correct Name of Sponsor and their URL and the image name (remember image must be 125x125
Save
Close
The DEFAULT image is found in the /classipress/images folder called ad125.gif
I copied the original calling the new ones ad125a.gif, ad125b.gif,ad125b.gif,ad125d.gif, and simply made the sponsors logos as those files.