Footer custom css

I would like to change the ‘PROUDLY presented by wordpress…’ on the footer to '© Manchester Medical Society 2015. All rights reserved. Website created and maintained by Priyanka Nageswaran’
is there a custom css as i don’t really want to mess with the original editor settings. if not, could you show me how to insert this into the original editor css.

It’s easy for you to change the copyright by installing footer copyright plugin

Look whether this may help: