[FMX] Textbox's counting up?

Hey all,
ok lets first start with my settings:
i have a dynamic text box with the var: counter, instance: c2
i have a MC on the screen with the code


onClipEvent(enterFrame){
_root.counter ++;
}

i want to put some coding on the frame they are on to say, when the text box counter reaches 200, gotoAndStop(2);
but i was puzzled as to how,
thanks alot,
Ben (flashy22)