dana marie mckinnon , 24 , charged with dui manslaughter and vehicular homicide .
florida highway patrol says mckinnon , then 21 , slammed into minivan on vihn vo , 42 , killing him on the spot in may 2013 .
mckinnon 's blood-alcohol level was more than twice the legal limit .
vo was owner and ceo of vector planning & services , a company that provides it services to military and federal and state agencies .