Without the datasheet for your device, it's impossible to resolve it for you, but here's the data for a typical device:
http://www.arroyoinstruments.com/thermistors.html It has a table of values vs temperature. So, at -10C it's about 55Kohm, and at +50C it's about 3.6K ohms. So now you need to turn that into a voltage either using a resistor divider, or a current source. This is simple math, easy to do with Excel, and you can create a list of voltages for each degree or half degree or whatever you like. Then use those voltage values to lookup the corresponding temperature.