V XLS2003 pouzivam toto:

' Zisti rozsah tabulky(A1,xy)
Range("A1").Select
On Error Resume Next
myLastRow = Cells.Find("*", [A1], , , xlByRows, xlPrevious).Row
mylastcolumn = Cells.Find("*", [A1], , , xlByColumns, xlPrevious).Column
myLastCell = Cells(myLastRow, mylastcolumn).Address
myrange = "a1:" & myLastCell