I dont know if i can trade in my iphone 5 for a iphone 5s

I've had my Iphone 5 for about 2 years now, its in good condition. It even has a $10 screen protector. But there's a piece coming out from the top, which i used "forever" glue from further damage. The screen is coming out from the middle, as well. I'm afraid if water gets in it'll just ruin the screen from the inside. There is no cracks, just few dents and chips. Because financial problems I'm afraid to go to an apple store and told that i have to pay for a replacement. But i also have a two year warranty, which expires on May 10, 2015.