Good that you are getting some data
What voltage are you getting from the temp sensor?
Now the datasheet gives the ohm of the temperature
so now we need to do some calculations.
You really need to work from a value given from the table, and by far the most accurate value to reach is the 0C, if your room is excactly 25C then fine use 25C
If you use the 0C, place sensor in plastic bag, crush icecube and place in another plastic bag and add a tiny amount of water to wet the crushed ice. Tie ice plastic bag tightly and wipe any moisture/water from the outside. Place icebag on top of baged sensor, The ice holds excactly 0C while melting!
Now read the voltage value from the Arduino (convert the 0 to 1023 value to voltage).
The formula for Amps = V/R (voltage divided by resistance)
The Arduino outputs 5V so if you read 4V then the voltage drop is 1V (5V - read value).
Amps = 1V/163810 Ohm
The amps should remain constant, so now that you have the konstant of I (amps) then you can find the voltage drop for the other temperatures by multiplying I*R = V (where I is your constant and R is the resistance of the table above).
The resistance drops when warmed up so it will eat less voltage.
I recomend to make another excel plot from the table above but with calculated voltage instead of Resistance:
X-axis: Voltage (or 0-1023 digital values)
Make regression line and note the formula.
Be careful with water and electricity