The antennas are really designed for a fixed installation, but you should be able to make a portable mount for them. It would probably work better for the 7dB unit as it's not as long as the 11dB unit and also would not be so sensitive to direction.
The frequency range spans up to 2.5GHz, so it should cover WiFi, but that's just an educated guess. Best bet would be to check with Poynting direct or use a dedicated WiFi antenna.
The antenna provides a certain amount of gain, indoors or outdoors. But, at these frequencies, you get a substantial loss of signal just by moving indoors, normally more than what the antenna can make up.
So the best bet is always an external, fixed installation.
Using it in a car is quite intriguing. Need to ask: Why?
Your biggest problem will be to find the correct direction to point the antenna.