AudiForums.com - 2010 Audi s5

looking for help i have a 2010 audi s5(automatic) and keep it short but was driving and white smoke comes out from A/C vents and hood and gas leaking out from bottom and car shuts off. I fixed the gas line but was wondering if the whole engine if toast? Would i have to get a used engine or can i just replace the short block on top please any advice will help plz and thank u