The Architect's Newspaper had the details in April 2010 on what all this will look like. According to the story:
The Department of Design and Construction (DDC) has commissioned Deborah Berke & Partners to complete a $16 million renovation of the aging structure and bring it up to current code requirements.
While the crux of the commission involves upgrading the 1894 building’s outmoded ingress/egress routes and substandard mechanical systems, Berke also saw the opportunity to improve the interior and how it was organized. The center’s primary inhabitants — PS 122 Gallery, Performance Space 122, and Mabou Mines — all grew into their rooms organically over the years, without much thought about how they functioned as a whole.
The construction is expected to be done by the summer of 2013.
And now that I've buried the lead... PS 122 is holding its final performance at this space