Install FreePBX into existing Asterisk 11.5 installation?

I work for a company that has a very integrated Asterisk 11.5 installation currently in place. We would like to add FreePBX to the existing installation without losing any of the call database or configurations. A software developer had integrated a custom CRM into the call database, including call stats and recordings. This data needs to be retained in order for the client listings to stay accurate. Said developer had extensive Linux knowledge, currently, there is no developer on staff and that leaves myself (network manager, Cisco/Microsoft background) to manage the current environment.

Is this something that can be done? If so, is there a how to for Linux dummies that I can use?