amplifying out signal of germanium diode
You are misunderstanding what the Ge diode does. If your signal is 2V then the Ge diode passes the rectified voltage minus 0.3V. 

However, it won't really work because there is nothing to discharge the coupling capacitor C6. A resistor from D1/C6 junction to ground would help.  

If you want to make a frequency counter front end I would suggest reviewing publicly available designs. Depending on the frequency, a JFET and/or an ECL gate may be useful. Here is one that is useful up to tens of MHz. There are many copies of this, originally from Weeder Technologies. 

The HC132 is a Schmitt trigger input NAND gate which behaves similarly to your 74HC14, so you can ignore it and the PIC.