I'm not sure, but I think what you're asking is to identify the last
column and then set the print  area accordingly. I understood that
your "last row" is set already at 710, but in case you need to
identify the last row and column  (i.e. the lastcell used on the
spreadsheet), here is one option:

Sub FindLastCell()
Dim LastColumn As Integer
Dim LastRow As Long
Dim LastCell As Range
If WorksheetFunction.CountA(Cells) > 0 Then
'Search for any entry, by searching backwards by Rows.
LastRow = Cells.Find(What:="*", After:=[A1], _
SearchOrder:=xlByRows, _
SearchDirection:=xlPrevious).Row
'Search for any entry, by searching backwards by Columns.
LastColumn = Cells.Find(What:="*", After:=[A1], _
SearchOrder:=xlByColumns, _
SearchDirection:=xlPrevious).Column
MsgBox Cells(LastRow, LastColumn).Address
End If
End Sub

Then, set the print area with:
Range(Cells(1, 1), Cells(LastRow, LastColumn)).Select
ActiveSheet.PageSetup.PrintArea = Selection.Address