The car should come with two keys & it sounds like the dealer is trying to fob you off (sorry about that pun), Only one of the keys supplied with the car when new is a remote, though. Replacement keys can only be ordered through main dealers, are frighteningly expensive & require the car to be reprogrammed to accept the new key. This cannot be done remotely & you will need to take the car to a FIAT dealer for the programming. Make sure you are sitting down before you ask the price - you have to pay to get the electronic key code, which is kept on a central register, you have to pay main dealer prices for the key (which has to be ordered from FIAT), and you have to pay for the programming.
Sorry to be the bearer of bad news.