I read a table from a txt file as follows. How to insert empty/filled columns/rows after import the table?

#+begin_src emacs-lisp
  (org-table-import "ttt.out" nil)
#+end_src

The file ttt.out will be:

#Cluster   Frames   Rep RepScore   Rep RepScore
       0      23      2      0.6     6      0.4 
       1      10      5      0.1     3      0.5
       2       5      4      0.4     5      0.6
       3       4      1      0.4     2      0.6

The results I need (new A & B columns and new rows, column A filled with 1 to length of rows).

| #Cluster | A | Frames | B | Rep | RepScore | Rep | RepScore |
|        0 | 1 |     23 |   |   2 |      0.6 |   6 |      0.4 |
|        1 | 2 |     10 |   |   5 |      0.1 |   3 |      0.5 |
|        2 | 3 |      5 |   |   4 |      0.4 |   5 |      0.6 |
|        3 | 4 |      4 |   |   1 |      0.4 |   2 |      0.6 |
|        5 | 5 |        |   |     |          |     |          |