As your data is in Access, why bother with Word.  Use the Report Label
Wizard in Access and at the end of the Wizard process, use the option to
modify the report design and then from the Access File menu, selectse Page
Setup and go to the Columns tab and in the Column layout section of the
dialog, you can choose between Across and then Down or Down and then Across.

If you do want to do it with Word, you should be using a Catalog or
Directory Type mailmerge with merge fields set up in a table with two sets
of merge fields accross, with a <<Next Record>> field before the first merge
field in the second set of fields.  When you execute this merge, you should
get want you want, but in that you have to set up two sets of fields, it's
twice as much work as doing it in Access.

I'd setup a table without borders and create a label merge using the table
as the 'labels'
You will probably find http://www.gmayor.com/mail_merge_graphics.htm and
http://www.gmayor.com/mail_merge_labels_with_word_xp.htm useful.
Merge to a new document and add the supplementary information you require on
the page.