I am trying to use and external link that is updated each week based on a
week numbered file as below

=VLOOKUP(E3,'G:\Mike\In progress\Sameday Product Analysis\[Sameday Database
2010 Values Week 19.xls]Database'!$E:$BH,$M$3+2,FALSE)

Is it possible to use a reference to another cell to change the week number.
Ie if i use a formulae as below it will generate the current week number i
report on.

=WEEKNUM(TODAY())-2

The idea being is there a formatt to allow the 19 in the above formulae to
be a refference to a cell and therefore will auto change the link or is this
not a function of excel?