If the processor is idle, it'll have a lower frequency. My C2D E6300 drops the multiplier down to x6.0 when it's idle, dropping the core speed to around 1.6GHz. When I put some load on the CPU it raises the multiplier to x7.0, so the core speed goes to 1.8GHz. That's just the speedstep stuff in Intel's processors, it saves power. Nothing to worry about.
The temp reading is probably software-related. That's not a problem unless you need to monitor your temps (like when overclocking). Maybe you should try some other programs to see if it's just a glitch in the program.
A couple of degrees difference in temperature between cores is normal.