macro in excel 2000 to produce a file with a filename/path based upon a cell reference

i require some help in writing macro in excel 2000 to produce a file
with a filename/path based upon a cell reference.

i have recorded the following macro in excel which produces a basic
csv output file based upon data that sits within a range within my
workbook.  i am a bit of a novice at macros, and I bet you all think i
am lazy for recording and not writing one ! this works fine for me. 
however, as you will see the filepath is specific to my username. 
this workbook is designed to be used by others, and what ideally i
would like to do is to have a cell within the workbook (for the sake
of argument <control and reference>, cell a1) which would contain a
for the output file.

here it is:

>>>>>>>>>
Sub chAmbient()
'
' chAmbient Macro
' Macro recored 10/09/2003 by John.Fairhurst
'

'
    Application.Goto Reference:="csvAmbient"
    Selection.Copy
    Workbooks.Add
    Selection.PasteSpecial Paste:=xlFormats, Operation:=xlNone,
SkipBlanks:= _
        False, Transpose:=False
    Selection.PasteSpecial Paste:=xlValues, Operation:=xlNone,
SkipBlanks:= _
        False, Transpose:=False
    Application.CutCopyMode = False
    ChDir "C:\Documents and Settings\john.fairhurst\Desktop"
    ActiveWorkbook.SaveAs Filename:= _
        "C:\Documents and
Settings\john.fairhurst\Desktop\chAmbient.csv", FileFormat:= _
        xlCSV, CreateBackup:=False
    ActiveWindow.Close
    Sheets("control & reference").Select
    Range("A1").Select
End Sub

>>>>>>>>>
which parts of the code to i need to alter and with what code ?

many thanks in advance.

john.