wp site infected

Okay,so i have a site that was hit by panda1,but still gets little traffic from y! and bing so i dont check back only every2 weeks.This morning i wanted to check and update the plugins and what i got is a warning from my antivirus.The theme is a free one from WP as well as plugins.What can be done?Is it a delete/reinstall?

Can help you, pm me