Finding Kp at another temp with /\Hrxn Took a pic of the paper I tried it on it on, has the exact problem description written at top, and what I tried. Figured that would be easier then typing all that. The answer is supposed to be 2.0.
You used the wrong version of $R$.  Try using $R = 8.314 J mol^{-1} \ K^{-1}$.