Use string manipulation to break off the parts. So you could use something like:
<%
'====================================================================
' Function will get the file name from the full path.
'====================================================================
Function extractFilename(pathName)
extractFilename = Mid(pathName, InstrRev(pathName, "\"

+ 1)
If extractFilename = pathName Then
extractFilename = Mid(pathName, InstrRev(pathName, "/"

+ 1)
End If
End Function
%>
The function just searches from the end of the string, for the first slash, indicating the start of filename. The VBscript language reference is very useful for such things as they have a different approach than some other langauges like Java.
I recommend downloading the whole thing, it has helped me no end.
There is a link to downloads on the left
bj