Web Site Security is something anyone with a website need to be aware of. Trying to harden your site is not an easy task as I have been learning throughout this long morning of working on my own site.
First when you find a hosting company look over their end user agreements and see what they offer on their back end to keep your site safe and secure.
My first word of advice to you is as your site grows and becomes more popular keep finding new ways of locking it down. Most hackers will not dig to deep into your site if there are not many people visiting it. It pays to look for numbers when you are looking to infect machines on the Internet.
My best word of advice is to do a Google search and find people on the Internet that will teach you steps to help you make a safer and more secure site.