Temperature compensation resistor value for oscillator circuit
It should not be hard to find a 5.6K resistor- that is a standard E24 (5%) value. You could use 5.62K 1% too. 

Rt/Rz are not 'temperature compensating' resistors with a special tempco, they are just normal resistors that bias the internal junctions to produce a voltage related to absolute temperature (Vt).. that way the temperature compensation circuitry is measuring the temperature directly on the die- it actually is there to compensate for the logging transistors which are also nearby on the same die.

The values of Rt and Rz don't change with supply voltage because the voltage at pin 3 is regulated to -6.5V by the internal Zener. Change the value of Ree to maintain that same current from your negative supply if the latter is not -15V.