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Impedance matching

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Hi there,

for a school project I try to recreate a given circuit, which receives a 457khz signal.
The circuit:

L1 and C7 form the resonant circuit, which I already have tuned to the right 457 khz frequency. The Filters are SFULA455 Bandpassfilters by Murata and the IC is a SA605D.
My Problem for now is the sizing of the capacitors C5 and C6. I understand that these are used for impedance matching between the resonant circuit and the filter. I have searched a bit and read some things about this, but to be honest didn't quite get how to do it. How can I calculate C5 and C6? The Datasheet of the filter says the input impedance should be 3000 Ohm. How can meassure/calculate the impedance of the resonant circuit? Could anybody tell me at least rough values for C5 and C6?

Thanks in Advance
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