Generally, QTP exports uses Excel file for data 
paramaterization. 
Method 1)Prepare test data in Excel sheet and import into 
QTP data table. Using DataTable methods, user can easily 
parameterize data and access them through out the script.
DaTaTable Methods: Import, ImportSheet, Export, 
ExportSheet, GetSheet, SetCurrentRow, SetNextRow etc...

E.g: 
DataTable.Import "Excel file path"
testData = DataTable(columnName, Sheetname)
(or)
testData = DataTable(columnName, dtGlobalSheet)


Method 2)Prepare test data in Excel sheet. Instead of 
importing Excel file/sheet into Test script, create an 
Excel object in the script using CreateObject method. Using 
Excel object methods user can able access data from excel 
sheet.

E.g:
Set ExcelObj = CreateObject("Excel.Application")
ExcelObj.WorkBooks.Open "Excel file path", false, false 
Set currentWorkSheet = ExcelObj.ActiveWorkBook.WorkSheets
(1) 'first sheet
testData = currentWorkSheet.Cells(rownumber, 
columnnumber).Value 
ExcelObj.Application.Quit

May be solution i'm providing is not a DataDriven but it is
useful.

We can access the object property at runtime and then append
something in the property and then again insert into the object.

Like we have a text box amount having value = 10

So we can use

value1 =
Browser(".*").Page(".*").WebEdit("amount").GetroProperty("value")

value1 = value1 + 1

Browser(".*").Page(".*").WebEdit("amount").Set value1