The K667 is an analog microphone and doesn’t include an onboard ADC. All analog-to-digital conversion is therefore performed by your computer’s internal sound card.
You can try cranking up the computer input level to 80% and speaking much closer to the mic at around 3 inches. And it still doesn't turn any better, consider getting an external sound card. Let it do the job of conversion and send a digital signal to the computer. You would be able to sound louder over time.