What i need to repair and price of repair

I have a 2005 ford 500, while driving the stalled out on the freeway and ideled down to only about 5 miles, no matter how i passed on the gas. i was told by a ford dealer I need throttle body and sensor and the cost would be 1200. Does both parts have to be replace, and is that a bit high for the repair. I have only had this car for 5 mos, which i 6500 cash for it, I am very upset because I dont have 1200 to buy for those kind of repairs. I see there have been alot of complaint about this problem with those car. thanks in advance