HH has 21 Studios and 21 1BR villas. These are all lock-off 2BRs and a few are HCA. 16 are located in the main lodge and the other 5 are found beneath one of the 5 GVs.
In general, Spring Break weeks will find the resort pretty busy along with June - August and Thanksgiving and Studios and 1BRs go quickly. Since there are many more 2BR villas (all dedicated) they are the last to disappear from Member inventory. Many have reported success over the years within 7 months for Spring, Summer and Fall reservations.
At this moment, there are both 1BR villas and Studios still available for 4/21 - 4/24, 4/28 - 5/2 and also for the first week in June (Sunday - Thursday) - but that could change at any time.
You'll never know until you call MS or look online. A non-home resort stay beginning on April 21, 2013 may be reserved on September 21 so you only have about 3 weeks to wait.
Good luck!