bthey will ONLY give you a iphone 4s and it will cost you 199$ to get it replaced
You won't get an iPhone 5 unless you buy a full upgrade on your plan. However, given that your phone is under the original one-year warranty, they will probably give you a replacement for either $99 or $149. Otherwise, visit your local high-end mall. Many of the little stands in the middle of the hallways do iPhone screen replacements while you wait, and it tends to be cheaper than Apple's prices to exchange.