I'm sorry you had to buy those analog thermometers, because they are garbage. Go out and buy yourself either two digital thermometers that have probes or you can pickup the accurite weather station. You can buy it from walmart or the home depot (not sure if they still sell it). It is a really basic unit but it is all you need. It measures outdoor temp with a probe, indoor temp at the unit, and indoor humidity at the unit. For the money (about $12) it is well worth it.
I am willing to guess that by the time you get a good digital thermometer you will get much different readings.
For now I would turn your habistat down, just incase it is too hot.
I assume by probe you mean the one to the thermostat? If so, then you got the placement right.