Renault clio 172
Hi , looking for some information / help with my clio . Got a 172 was running great until I got a flat battery , wouldn't start so I jump started it took it a drive was again driving good . Went to start it next day battery was dead , needs a battery after some investigation , however left it for a week and jump started it yesterday , and it sound really lumpy , took it for a drive and the management light was flashing and was severely down on power , I turned it off as didn't want to damage it , any1 any ideas what it could be ?