You never know until you call. Easter in 2005 is March 27 so I'm not sure if you count that as the 3rd week.
March is the height of the season in Vero and the number of 2 bedrooms is limited. However, things change all the time and some time on the wait list may get you what you want. You might want to consider a back-up plan. Would 2 inn rooms work for your group?
We have gone twice in May and never had a problem with booking a month or two ahead (BWV is our home resort). It is a wonderful resort our favourite after GF you will just love it. Have a wonderful time!