If you want a whole bunch of them, you should consider making use of this date function...

http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=61519

select DATE, ISO_YEAR_WEEK_NO from dbo.F_TABLE_DATE('1/1/2008', '1/1/2009')

Better still, use that function to create a permanent, fully-indexed table, and then use that.