External Link in Byline Date

I would like to link the byline date to the relevant "BBC on this day" page. Is this even remotely possible? I realise I might have to manually select the correct BBC link for each date as I post but that's no biggie. The difficulty I face is getting the date to link to anything! If this is really easy and I'm missing something obvious feel free to ridicule.. I'm still not that familiar with HTML, CSS, PHP and whatever other acronym may be relevant.
Anyway, I absolutely love this theme. Awesome and Wow are my two most used words at the moment.
This is the site I'm working on, hope someone can help, thanks