Back link in Top Menu

Hi all,
I have installed Piwik both on my production server and on my WAMP testing server.
I would like to add a link in the top menu allowing so visitors to go back to my website.
I’m far away of being a coder and I didn’t set up Piwik for development ( so I’m not able to create a new plugin ).
With my older Piwik installation, I managed to add a link directly in the tpl file. I would like now to avoid such trick being able to upgrade Piwik without problems.
Is there a quick and easy tutorial for that purpose.
I would suggest that this option should be included in the administration option…allowing not expert people to add this link.
Thanks in advance for your help.
PS : my Piwik version is the latest.