I'm going to create a new website with Joomla! 3.
Potentially, this site will get me some money through ads but I'm a little worried about what could be done to attack it. I say a little because I'm not hoping in huge revenues and I don't think someone will try to bribe me into giving them control of my site (like it happened to the owner of the @N twitter account), but when dealing with black hats you never know.
I do not need to provide public authentication or to have people other than me input data on this website (I might accept inputs via mail and copy-paste them by hand after checking their content, since I want the writing quality to be good and consistent with the resto of the site).
I will use free Joomla! themes - the basic ones included with the standard installation might do fine.
Is there any threat that I, as a security noob who understands a little about how the Internet works (let's say just enough to understand Heartbleed), absolutely need to protect from?
Should I hire a professional developer for my project, or are there just a few things I should do to protect my site reasonably (making hacking not worth the effort) that I could learn about in, say, under a month of an 8/5 worker's free time?