How to increase an output of opamp in this noise generator?
You've basically killed off the noise source by using a value of R2 at 100 ohms. This acts as an impedance to ground (virtual earth) and leads to only the higher end of the spectrum coming through because of the really low value of C1 (47 pF). It forms a high pass filter with a 3dB point of nearly 34 MHz.

Even if you increased C1 to 47 uF (3 dB point of 34 Hz), the loading effect of R2 is too high. Try using a non-inverting op-amp configuration - it has a high input impedance and should work much better.