Instead of handling the power only page, you want to handle the CTF page. Modify the script to have a method CrankTorqueFrequencyPageReceived instead of StandardPowerOnlyPageReceived.
You can then parse the page structure properties to csv in a similar way using the documentation in "SimulANT+ Scripting Interface.chm" for the CrankTorqueFrequencyPage structure to determine the properties that are available.
You can also choose to write the display values from SimulANT+ to csv instead of raw page values. Use simulator.CadenceCtf, simulator.PowerCtf, etc (see Properties for BikePowerDisplay Class in chm file) instead of page.*. Note that these will be values from the prior page rather than the most recently received page.
Ian