try using a PNP BC 557 transisitor intead of NPN BC 547; it seems like the output, at the very push of the button, becomes low. Try it out. Also now the transistor would be connected like this:
1. Base connected to pin1 of IC via a current limiting resistor.
2. Emmiter connected to VCC
3. Collector connected to anode of LED (+ive pin)
4. LED's cathode pin (-ive pin) grounded via a resistor.
This should work