Add some functions to Website

I want to make site where users can make their own blog easy. I was looking tumblr site and it’s looking ok. I have found copy of their script [login to view URL] that has main functions. Now I need programmer to add some functions in it. I want to add text in combination with pictures, audio, video files. So as example the member can add the picture (already have that option in the script copy) but to have the option to add text below picture too. Same is with video, links and other options in the script. Also I have seen that there is no text editor in script copy (so the users can bold or underline text). So need to add text and HTML editor with preview. In script copy there is only option to browse for files on own computer. Drag n drop function should be added too. When member paste the link of the video, thumbnail is not showing. Sharing button to main networks (Facebook, Twitter, Google+…) To simplify all, these are the functions to be added to site: 1. Adding text with editor and preview below each option 2. Drag n drop function 3. Thumbnail to be shown for the link 4. Sharing buttons I will have lots of work on the site. Change of template (to offer the users they can change template for their blog) making of homepage and so on. But I need to go step by step. By the way I will not have cpanel, so all the work will go with ftp. Hope this is not the problem if we make a deal.