Since FirstSortedValue takes a single sort_weight parameter, I believe you'd need to turn those three fields into one somehow:
1) In script by loading them in sorted order and adding a row number or autonumber field for sorting later
2) By concatenating them as a string (note - this will result in string based sorting rather than numeric)
3) By converting the Name column into a numeric value and adding the values up, e.g.
(ID * 10000000) + (Date*100) + ord(Name) // Note - this assumes Name is a single letter
