Well
Assuming you have the same circuit as described in the tutorial..
you can use the formulate, (which I have copied an pasted below, (from the link above)
How Does A Thermistor's Resistance Depend Upon Temperature?
The Steinhart-Hart equation gives the reciprocal of absolute temperature as a function of the resistance of a thermistor.
Using the Steinhardt-Hart equation, you can calculate the temperature of the thermistor from the measured resistance.
The Steinhardt-Hart equation is:
1/T = A + Bln(R) + C(ln(R))3 R in W, T in oK
The constants, A, B and C can be determined from experimental measurements of resistance, or they can be calculated from tabular data.
Here are some data points for a typical thermistor from "The Temperature Handbook" (Omega Engineering, Inc., 1989). (By the way, when you refer to this thermistor, you would say it has 5kW at room temperature.)
T (Deg-C) R (W)
0 16,330
25 5000
50 1801
So your numbers are a little out as to the tutorial, I expect that you can change your stuff to be similar to the tutorial.
at least you will get numbers you can relate to..