ULTIMATE Call To Action adds call to action block with text and button(button text and link).
You can add unlimited blocks and set the background(it comes with integrated color picker).

It should work well on all OpenCart themes and supports responsive themes too.
It is cross browser supported and compatible with all mobile and tablet devices.

Demo: Frontend

Admin: Backend
Username: demo
Password: demo

Find out more on http://macedonius.com
Support is available at http://macedonius.com from live chat and from our support center http://support.macedonius.com
Email support on support-opencart@macedonius.com