Clearly you are clueless when it comes to this stuff.
You need to tell us what it is you are trying to protect. Usually that means securing and protecting your database.
I suggest you hire a skilled sys admin and get a server in a large data center. Not some data center maintained by some Joe shmo.
You need to secure your website from the OS level down to the script running your application. I assume you had a web based front interacting with a back end database. There are numerous technologies but you can't go wrong with MySQL for database and python or php for the web backed. NodeJS is a new popular alternative as well.
The most common point of entry is your application. The web backed. If you use public software such as this forum then the odds of exploitation increase significantly. Properly coded custom scripts are pretty secure if developed by a competent developer with security in mind.
Make sure to keep your database, OS, and web server technology up to date. For web server I recommend nginx. The Russians set a new standard with that.
SSL will secure your communication between the server and client. Man in the middle attacks are pretty common these days. End to end encryption is always recommended especially when communicating sensitive information.
As i said before I suggest you speak to a highly skilled sys admin and some talented backed developer with focus on security as you seem pretty clueless.
I doubt anyone here can give you any pointers until you explain what it is you are trying to protect and secure.
You can never go down if you think like a blackhat and leverage some common sense.