New install with existing site

I just purchased your lifetime license for the Music City template. I used a Rocket theme template which has Gantry installed as well. My question is the following in order to avoid any conflicts I would like to know if there is a way to use your Quick Start package but use my existing database since I have an extensive database and need to keep the data but I am concerned that there maybe a lot of conflicts between the two templates which I would like to avoid.

I have never used your system and would like to avoid any additional work if possible.