Modify/duplicate, edit Links Widget

I’d like my links widget to be able to only show five most recent links, but also show the date they were added. I would think I could either modify the links Widget or duplicated it and edit the second one so I’m not changing the core function of the widget.

any ideas if there is a plugin for this or how to get started? I have searched my installation code, codex, etc. and I’m not having any luck.

Thanks.