Apple is reportedly planning to have the store open by the end of July or beginning of August.
The leasing plan for the mall [PDF] shows the expansion in progress, with a Microsoft store located right next door to Apple in part of the space vacated by Williams-Sonoma and Pottery Barn. The newly expanded Apple Store will be twice the size of the Microsoft retail store, which opened last August.
IFO Apple Store has additional information about the expansion from a post last year:
The Apple store opened in September 2005 with about 2,700 square-feet, now a considered a small space for the large number of daily visitors. According to insiders, the Williams-Sonoma and Pottery Barn stores will soon vacate, although it’s unknown if they’re relocating to other spaces in the mall or closing completely. Shortly after, construction will begin to expand the 30-foot wide Apple store into a portion of the adjacent vacant space. Mall lease plans suggest the finished store will have a 90 foot-wide storefront with 8,640 square-feet.As Apple has covered much of the United States with retail stores, in recent years the company has been focused on expanding existing locations rather than building out new ones.