The emitter circuit is independent from the LED/IR detector circuit, so R1 will not be affected.
The slight change in voltage drop across a blue LED compared to a white LED would not be significant enough to need to change values of R2.
R2 directly affects the balance between the allowable distance between the IR emitter/detector and LED brightness (higher value = allowable IR emitter/detector distance increases, but LEDs are dimmer; lower value = allowable IR emitter/detector distance is decreased, but the LEDs are brighter).
You may need to play with the value of R2 a little bit to find a good balance for your semiconductors, but the values I posted should be just fine.
Blue 5mm LEDs
Threaded Mode
