Code To Add Data To Next Available Row

I am "pushing" information from MS Word Fill-In Fields to Excel. Currently, the code (which is intended to run in Word) is overwriting the "pushed" data in the same cells in Excel (row 1). I would like it to add new data to the next available rows [kind of like the End(xlUp).Row + 1 code, but for Word].

Dim Fld As Field
Dim ExcelSheet As Object
Dim iColumn As Integer
iColumn = 1
Set ExcelSheet = CreateObject("Excel.Sheet")
ExcelSheet.Application.Visible = True
For Each Fld In ActiveDocument.Fields
ExcelSheet.Worksheets(1).Cells(1, iColumn) = Fld.Result
iColumn = iColumn + 1
Next Fld
ExcelSheet.SaveAs "C:TEST.XLS"
' Close Excel with the Quit method on the Application object.
ExcelSheet.Application.Quit
' Release the object variable.
Set ExcelSheet = Nothing
End Sub