Communication distance is almost totally dependent on the design of the RF hardware and the RF environment (RF noise, line of sight, antenna orientation, etc) but typically ANT nodes like the USB stick are designed with approximately up to 30m - 50m of range with line of sight in mind.
It is absolutely possible to boost the signal power using external components, but it's uncommon as ANT is typically going into commercial products meaning ANT modules have been designed to stay within FCC and other regulatory specs regarding maximum signal strength.