Add an image to a sidebar in a custom template

I've been customising a client's site and am stuck on one request they have. They want an image underneath the page title on the left hand sidebar of this page: http://www(dot)gflooring.com/newsletter/#.UpSCro1Rvgw

You can't use the normal widget area as these seem to have been overridden by custom templates and I can't work out how to add something to this page sidebar in particular, without affecting other page sidebars.

Any help would be greatly appreciated.