make three additional variable that would serve as a counter. For example count1=1, count2=2, count3=3. then rename your textfield to tf1, tf2, tf3 <- this would lessen the confusion since you are using the same variables in your textfile.
on the first frame load the text file:
loadVariable("yourtext.txt","");
on the third frame place a stop action. leave the second frame blank. your buttons and text field should be on the same timeline and on must be present at the third frame.