Add a 3 column table to the bottom of a word document using c#

Hi Experts,

I'm attempting to create an ActionsPane in word that will allow users to add comments to a table at the bottom of the document, so that as they are reviewing the document, they can add an entry into the word table by entering the comments in the actionspane and hitting a button.

So how would I go about:
1.  Seeing if a table already exists (lets call it CommentTable); if it does move on to step 2, if not, add the table with 3 columns of 1"; 1",4.5" widths.
2.  Add a new line to the bottom of the table; there will be 3 fields called Section, Reviewer, Comment with data from the actionpane.

Thanks for the help!
Deedub84