Передача параметров ADO запросу

CONECT_STR='Provider=Microsoft.Jet.OLEDB.4.0;Password=" " ;User ID=Admin;'+{Data Source=D:\ExBd\ТЕРМО\Bd0.mdb;}
                                'Data Source=%s; Mode=Read|Write|Share Deny None;Extended Properties=" " ;'+
 'Locale Identifier=1049;Persist Security Info=True;Jet OLEDB:System database=" " ;'+
 'Jet OLEDB:Registry Path=" " ;Jet OLEDB:Database Password=" " ;Jet OLEDB:Engine Type=4;'+
 'Jet OLEDB:Database Locking Mode=0;Jet OLEDB:Global Partial Bulk Ops=2;'+
 'Jet OLEDB:Global Bulk Transactions=1;Jet OLEDB:New Database Password=" " ;'+
 'Jet OLEDB:Create System Database=False;Jet OLEDB:Encrypt Database=False;'+
 'Jet OLEDB:Compact Without Replica Repair=False;Jet OLEDB:SFP=False';

function TdmR3.GetCountForPeriod(LastDate: TDateTime; IsPlan: boolean): Integer;
 var qu: TADOQuery;
 S: String;
begin
 qu:=TADOQuery.Create(nil);
 try
 S:=FormatDateTime('dd.mm.yy',LastDate);
 qu.ConnectionString:=WideString(Format(CONECT_STR,[db_file]));
 qu.SQL.Text:='select count(*) from DecadaVal as d where d.LastDate=:LastDate and IsPlan=:IsPlan';
 qu.Parameters[0].Value:=LastDate;
 qu.Parameters[1].Value:=IsPlan;
 qu.Open;
 Result:=qu.Fields[0].AsInteger;
 finally
 qu.Free;
 end;
end;