Get Data From Xml

I had write an asp file to get data from an xml named "data.xml" and below is the coding:

Dim xml
Set xml = Server.CreateObject("Microsoft.XMLDOM")
xml.async = False
xml.load (Server.MapPath("data.xml"))
Dim fText1, fText2
fText1 = xml.documentElement.childNodes(0).text
fText2 = xml.documentElement.childNodes(1).text
Set xml = Nothing

It's all Ok and can run. But my problem here is I want to call an xml file that I don't know its name (not "data.xml"). The xml file pass by the user who call my asp file. The user can pass the xml via anything for example asp or VB component. So I will not know exactly what the name of the xml file.