About the Audio Player; It depends how your current player receives its information about which file to play. It may be as simple as simply replacing the current player with a different one and changing a few settings, or a whole load of customization. You'll have to tell us more. although most likely it'll just be a simple change of switching it out for a different player.
Now onto whether you should learn the technical skills to administer your own site. If you're looking to modify your own site(CSS design, PHP) then it will take you quite a while to learn, and it is time consuming, its up to you whether you want to trade time for money by hiring someone out. If I didn't have the technical skills I would definitely hire someone.
But I strongly recommend you learn the basics of website administration. Also things like "Creating a database to capture emails" isn't really that hard to do , and I expect you could learn it quite easily. Be aware though, that being able to do it doesn't mean that that is the way it's supposed to be done. For example, many people new to PHP and database tend to leave gaping security holes that allow for SQL Injection attacks very easily.
That's my suggestions. If you do decide to code your own scripts, remember this, always treat your users and their input as malicious unless proven otherwise. You must always sanitize any and all input you receive, even if you are sure it is clean, you can never be sure. Another thing, explicitly define what you accept in your scripts(i.e. a while list) meaning instead of saying "I wont accept $, %, or # symbols" you will say "I only accept !,@,^ symbols" .
I know I went off on a tangent there, but I feel not enough people know this
Hope this helped.