Hi,
There actually is a way to refine your search criteria on RedWeek. Please go to our home page, then click on the "Show dates, beds, etc." just under the search form on the right side of the page -- directly under the orange "Find a Timeshare" button.
The link will expand the search options to include a date range, # sleeps, # of bedrooms, etc. While our advanced search function does not accommodate searches by week number, you can determine the date range for a week number by referencing our timeshare calendar at:
http://www.redweek.com/calendar/
Regards,
Alisa Stephens Customer Service Manager RedWeek.com
Alisa S.