2011 Volkswagen Golf very low power, with smoking

My 2011 vw golf recently broke down , and refused to start again. on checking it was obvious the serpentine belt was disintegrating, so i replaced that. it still didn't run so we looked at the timing belt and found that due to a piece of the serpentine belt getting stuck in the timing belt, it had slipped a few notches. We returned it to its regular spot. it now runs fine, but doesnt rev past 2500, and it smokes a good bit, with very low power. any ideas?