Adding multiple HTML pages as nodes as part of workflow
Tahnoon,
This is a very unusual task you are trying to perform. Typically we use Drupal to generate new content and manage how that content is displayed. As you have experienced, there are a couple mechanisms in place to import data from databases, spreadsheets, CSVs etc, but not an easy way to import existing HTML files from a specific directory.

What you are trying to do CAN be done but it will take a certain amount of PHP coding [not a whole lot] to write a custom module that would do this.  

Since your request is not a common case, you will not find a tutorial for it that exactly meets your needs. Rather, you will have to learn PHP and Drupal Module development techniques and write code to find that directory, parse through each file in it, extract out all of the markup between  and  and place it in the body field, change the filter to FULL HTML, take the file name and use it for the TITLE.

I can't possibly use StackExchange to teach you all of this, so I'll just get you started.
1] get friendly with http://api.drupal.org this is where we store all of the documentation on the Drupal API
2] specifically look up the hook_menu implementation and create a page where your custom code will fire [for this purpose you're going to hardcode the directory rather than build a user-interface that asks for it.]
3] study up on the family of Drupal file functions. I don't think you'll need any generic PHP file functions, but it could happen.
4] download and install and enable the Examples for Developers module  There is one example in there that is FILE related and it saved me A LOT of work last month.
5] You also need to look at the Google results on how to programmatically create nodes http://goo.gl/A3hUP4 there are a few ways to do this.

Those 5 steps should get you where you want to be. Since you're somewhat new to PHP and Drupal this may take a long time, but it will be a tremendously great opportunity to learn!

If you can afford it, you may want to pay someone to build this OR to help you build it so that you learn in the process.

I hope you find this helpful! :-)