Open Excel file, change it and save it

[adi.shoukat]

I need to do the following:
-> open Excel file
-> change values of required cells
-> then save the file

right now I am doing this:

Excel.Application xlAppoutput = null;
Excel.Workbook xlWorkBookoutput = null;
Excel.Worksheet xlWorkSheetoutput = null;
Excel.Range rangeoutput = null;
try
                {  
                    xlAppoutput = new Excel.ApplicationClass();
                    xlWorkBookoutput = xlAppoutput.Workbooks.Open(@"D:\Askari9\output\myFile.xls", Type.Missing, true, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
                    xlWorkSheetoutput = (Excel.Worksheet)xlWorkBookoutput.Worksheets.get_Item(1);
                    rangeoutput = xlWorkSheetoutput.UsedRange;

                    //(rangeoutput.Cells[12, 3] as Excel.Range).Value2 = "new value";

                    xlWorkBookoutput.Close(true, null, null);
                    xlAppoutput.Quit();

                    releaseObject(xlWorkSheetoutput);
                    releaseObject(xlWorkBookoutput);
                    releaseObject(xlAppoutput);
                }catch(Exception ex){
                    System.Console.Write(ex.StackTrace);
                    System.Console.Write("System could not successfully generate bill for House#" + Reader.GetValue(houseNoFieldIndexInDB).ToString()+"\n");
                    releaseObject(xlWorkSheetoutput);
                    releaseObject(xlWorkBookoutput);
                    releaseObject(xlAppoutput);
                }

I get an exception on 'xlAppoutput.Quit();'

Can anyone please help me fix this? or tell me any other way of doing the same job (open excel file, change it then save it)