(setq map "+----------+
|..........|
|..........|
|..........|
|..........|
|..........|
+----------+")

(defun where (row col)
  (+ (* row 13) col 1))

(progn
  (switch-to-buffer "*map*")
  (insert map)
  (goto-char (where 3 7))
  (delete-char 2)
  (insert "()"))