How to overwrite in my previous excel file using JXL?

I want to set the status of executing test but whenever I execute the code it create new workbook by using this line:

wwbCopy = Workbook.createWorkbook(new File(testSuitePath));

Now can anyone please let me know how I can set the status of executing test case.

For this I am using JXL lib. and in keydriven framework.

Below are the code of write in excel:

public class WritableData {

    Workbook wbook;
    WritableWorkbook wwbCopy;
    String ExecutedTestCasesSheet;
    WritableSheet shSheet;

    public WritableData(String testSuitePath, String string) {
        // TODO Auto-generated constructor stub

        try {
            wbook = Workbook.getWorkbook(new File(testSuitePath));
            wwbCopy = Workbook.createWorkbook(new File(testSuitePath));
            // shSheet=wwbCopy.getSheet(1);
            shSheet = wwbCopy.createSheet("Login", 1);
        } catch (Exception e) {
            // TODO: handle exception
            System.out.println("Exception message" + e.getMessage());
            e.printStackTrace();
        }
    }

    public void shSheet(String strSheetName, int iColumnNumber, int iRowNumber,
            String strData) throws WriteException {
        // TODO Auto-generated method stub

        WritableSheet wshTemp = wwbCopy.getSheet(strSheetName);
        WritableFont cellFont = null;
        WritableCellFormat cellFormat = null;

        if (strData.equalsIgnoreCase("PASS")) {
            cellFont = new WritableFont(WritableFont.TIMES, 12);
            cellFont.setColour(Colour.GREEN);
            cellFont.setBoldStyle(WritableFont.BOLD);

            cellFormat = new WritableCellFormat(cellFont);
            cellFormat.setBorder(Border.ALL, BorderLineStyle.THIN);
        }

        else if (strData.equalsIgnoreCase("FAIL")) {
            cellFont = new WritableFont(WritableFont.TIMES, 12);
            cellFont.setColour(Colour.RED);
            cellFont.setBoldStyle(WritableFont.BOLD);

            cellFormat = new WritableCellFormat(cellFont);
            cellFormat.setBorder(Border.ALL, BorderLineStyle.THIN);
        }

        else {
            cellFont = new WritableFont(WritableFont.TIMES, 12);
            cellFont.setColour(Colour.BLACK);

            cellFormat = new WritableCellFormat(cellFont);
            cellFormat.setBorder(Border.ALL, BorderLineStyle.THIN);
            cellFormat.setWrap(true);
        }

        Label labTemp = new Label(iColumnNumber, iRowNumber, strData,
                cellFormat);
        try {
            wshTemp.addCell(labTemp);
            System.out.println("writableSheet---->" +wshTemp); 
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    public void closeFile() {
        try {
            // write the value in work book
            wwbCopy.write();
            // wwbCopy.close();

            // Closing the original work book
            wbook.close();
        } catch (Exception e) {
            e.printStackTrace();

        }
    }

}