You cannot -layout- content in a textbox or textarea. You want to either go for TinyMCE as an iframe (where layout is broken relatively easy), or create separate inputfields for dates and logs (and layout using html/css).
TinyMCE has a table plugin that you can use. Have you tried that?
Search for "tinymce table plugin". Your example seems to be a 3x2 table.
You may also want to look into the TinyMCE template plugin.
Like Jeff Yang mentioned, you can use tables to help your users lay out their content without CSS (it makes me cringe, but yes on CMS-driven sites with users of all types editing content, I still give them a table to save me headaches).
The template plugin will allow you to set up your own table, lock it in place, and then let the users select it from a dropdown. So, you could set up a table to your specifications above, name it "2-column with dates" or something, and train your users to select that when they needed it.
The plugin also has a preview option so your users can pick and choose exactly which template they need.