Sharepoint backup application

Hi
I got a project to do, now I only started working with Sharepoint and come from  a web development background. Now I do not have a lot of experience and would gladly appreciate your help.
I need to develop a backup application for our shareoint sites and sub sites. For some or other reason which I can not figure out nou because I do not understand the whole backup thing....is that I was told not to use sysAdm or the default backup procedure in my code because it will not be working for what we are going to do.
So what I must develop is an application where you can choose sites,sub sites,custom web parts, master page etc etc. and the I can clcik on Backup and it will backup the site...??
 
I do not know where to begin
 
Jurie