Getting Data from GPIO

Hi All,
We synthesized a BPSK demodulator and sent the 1 bit demodulated dataalong with the clock to the GPIO pins
Our aim is to get the IQ data for Spectrum from the USB.
Our problem is to transfer the data on the GPIO to the motherboard of the PC and read it.
Is there a port on the motherboard where we can access the data?

Maybe this will help

Thanks for the suggestion, but the LMS C++ API read is done from USB.
What we want is to send the demodulated data and clock directly to the motherboard using cables.
But where in the motherboard, that was the question.