On the main timeline where you duplicate your movieclip add a score variable at the top before the loop. Lets assume you name it score = 0;.
Now on the cross hair actions, where you have the if statement to check that if the mouse is released and is hit testing the tiki's, increment the score by one:
I added a trace() so that you can see the score incrementing as you played. Of course, you would just replace that with maybe a dynamic text box that display the score for you: _root.myScore.text = _root.score;.
For some reason it deletes all of the tiki's that are displayed on the current screen when you click. Could you like make a video or something showing the step-by-step? If not, thanks!