Question : Reporting data from the last week in ssrs

I've written an SSRS report to list data where a datetime field is greater than the date entered in a report parameter. Problem is I need to schedule this to run now as a subscription to report all data in the last week i.e. each time the subscription runs it reports for the last week (dateadd(dd,-7,getdate()) in sql speak I guess!). Is it possible to set values against parameters in a subscription? I don't really want to change the sql up front to report from a week ago as I still need the flexibility to run the report from any date on request. Was thinking of creating a linked report may be and setting a default parameter value of a week ago, but don't know how to make this dynamic rather than physically hard-coding the date for a week ago.  

Answer : Reporting data from the last week in ssrs

=DateAdd(DateInterval.Day,-7,today())