Simplified form:
Last week data:
SELECT id FROM tbl
WHERE
WEEK (date) = WEEK( current_date ) - 1 AND YEAR( date) = YEAR( current_date );
2 weeks ago data:
SELECT id FROM tbl
WHERE
WEEK (date) = WEEK( current_date ) - 2 AND YEAR( date) = YEAR( current_date );
SQL Fiddle