Dear tajamal,
You can create a stored procedure which deletes the data you wish to delete.
Next create a job which executes the stored procedure. You can schedule the job to run once a week, or on any day in the week you wish.
A new job can be created in SQL Server Agent.To tell the job to execute your stored procedure:
Add a new step. Give it a name like 'Step 1: delete data from myTable'. Select the right database. In command box type: EXEC the_name_of_your_stored_procedure
Thank you for asking