Sorry to hear of your troubles. First you CPU problem is the use of mapping and gps. A better power balance may help. I would suggest rooting, ROM and possibly the PBJ kernel. It will greatly change the performance of the phone especially power management.
One of the hardest things on the phone is live real time mapping. Likely the second is wifi tethering depending on the app.
Hope that helps... at this time I cannot think of a cpu monitor, but they are out there.