GE likes to keep things tech info a secret so it makes it difficult.
They often use 2 elements to get different heat settings.
If this is the case then your 20 ohm approx coil resistance looks OK (see the wiring diagram at the end of this post)
Elements usually do not increase in resistance they either burn out (infinite resistance) or short to the case (Neutral).
Meter Usage.
A couple things to watch when measuring ohms and continuity
1. Always remove power from the machine otherwise you could blow your meter.
2. Always disconnect at least one side of any device you are checking. This eliminates the possibility of measuring an alternate/parallel circuit path.
3. When checking for closed contacts and continuity use the lowest scale (Usually 200 ohms). Then try higher scales. This scale is 0 to 200 ohms so if the device you are measuring is 300 ohms this scale would show an open circuit which it is not, you are just measuring outside the scale's dynamic range.
There is a good STICKY at the start of this forum about it's use.
Blown Thermal Fuse
If it is blown you have to find out what caused it to go.
Note: that sometimes they do just blow on their own but changing it without checking other things is a gamble. I believe richappy (another regular poster on this forum) has done a study on thermostats and found a wide variation of actual trip point and what is specified.
Check the heating coil.
Unplug the unit and both wires to the coil.
Check it with a meter, should be around 12 ohms.
Then check from each side of the coil to the case/frame, both should be infinite ohms (open). If not the coil may have sagged or broken and is touching the case. This can cause it to run on high and the thermostats cannot regulate it so the thermal fuse blows.
If the above is OK then you will also have to replace the hi-limit as it should have regulated the temperature so the fuse did not blow.
You still have to find out why it blew.
Check that the belt is OK.
Check the seals (drum etc) in the unit. The air is pulled over the heating coils, through the drum and pushed out the exhaust. So any large seal leak will pull in room air and the cycling thermostat on the blower will run the unit hot.
Check that the lint filter is not coated with fabric softener residue which greatly reduces air flow.
Check/clean your vent system.
Check/clean the blower wheel.
If all OK you may want to replace the cycling thermostat as it's contacts may not be opening (welded shut).
Here is a typical GE wiring diagram.
Please note this is a total guess on matching your unit.
http://www.applianceaid.com/newimages/ge-newelec-diagram.JPG