Jason beat me too it. Pretty sure that person who told you there's an app coming that will start your car is smoking crack.
And the person who got quoted $600 (or sort of made that up based on something they found online in infiniti parts) - was talking about the option for the JX35/QX60. All JX35's had remote start capability, you just needed to buy the key fobs and have them programmed. Since remote start is not an offered option for the Q50, I sincerely doubt that a keyfob with a remote start button is going to make it magically appear as a feature on the car. Oh, and two keyfobs including programming would cost over $500.