This circuit is based on a very old application note from exar, in this the frequency is fixed by IC1 and IC2 -P1 controls the duty cycle. you need to compute the R and C values to get what you need,
Fixed frequency var DC 555
You have to study the circuit and do something more innovative perhaps, just copying is ok for learning but it will get you nowhere, so learn and then innovate.
Forrest Mims engineer's mini notebook 555 timer circuits (radio shack electronics)