Code Change Help Needed

I am trying to figure out how to change this code:

move_uploaded_file($_FILES["file"]["tmp_name"], WP_PLUGIN_DIR."/" . $_FILES["file"]["name"]);
	      echo "Stored in: " . WP_PLUGIN_DIR."/" . $_FILES["file"]["name"];

So that it uploads files to the regular upload folder which is domain.com/blogname/files/year/month/filename.extension

I do not know enough about code to figure this out. Any help would be greatly appreciated!