AC Op-amp Integrator with DC Gain Control
The lower frequency is \$F_{lower} = \dfrac{1}{2\pi C R_2}\$

The upper frequency is \$F_{upper} = \dfrac{1}{2\pi C R_1}\$

The easiest way to consider the upper frequency is the gain being 0 dB or unity. At this point the impedance of the capacitor equals R1 (assuming that R2 is much bigger than R1 of course. Now

\$R_1 = \dfrac{1}{2\pi F C}\$ and you just rearrange R1 and F to find F.

For the lower frequency a similar method is used but this time the impedance of the capacitor is equated to R2. This gives the "so-called" 3 dB point i.e. the frequency at which the gain R2/R1 drops by 3 dB. So, if R1 and R2 produced a DC gain of (say) 40 dB the 3 dB point would be: -



Picture stolen from here - a useful site for op-amp basics.