Sarah,
the thermometers that stick on the glass measure the tempurature of the glass only. It is the tempurature of the surface of the repti-bark that you are interested in.
I had the same problem you are having when I first started. I used a stick on the glass type, I had it stuck on the glass on the hot side, and could not get it to go above 70 I then learned that that type of thermometer is USELESS. So I got 2 digital indoor/outdoor thermometers (they have em at walmart for less than 10 bucks) and put the temp probes at thge substrate level, one on hot side, and one on cold side. But the cold side thermometer is optional since that should be room temperature, but I like to glance at the viv and see the 2 temps. Anyway, guess what my temps were? a whopping 105 degrees on the hot side. even tho air temp was still 70.
Also Your snake should let you know if he is too hot or too cold. (mine does anyway) If he hangs out on the cold side all the time he is telling you that the hot side is too hot. and If he burrows under the substrate on the hotside he is looking for warmth, and it means he is to cold. So pay attention to where your snake spends most of his time.
As for your equipment, you will need a rheostat or thermostat to control the UTH along with a digital probe thermometer. Do a few searches here on this site for rheostat or thermostat to learn all about that stuff.
I have had my snake a month, and thanks to this board my husbandry skills have greatly improved, I couldnt have taken care of my snake without it. So read all you can.
Welcome to the board and good luck with your snake.