I am interested to learn morea about Alma Mahler-Werfel's last 20
years . After the death of Franz Werfel she moved to New York and died
there in 1964.
Where in New York did she live and what did she do ?

wienerin --

I believe that a comprehensive answer to your question can be found on
a single website, which is an Austrian site devoted to a touring
theatrical extravaganza that will be presented in Los Angeles from
September 30 to December 4, 2004.

Here is the home page of that website, which you may want to peruse
for lots and lots of other information about Alma Mahler:
Alma Mahler
http://www.alma-mahler.at/

Buried deep in the press-relations section of that website is a page
that gives  substantial detail about Alma's relatively quiet (compared
to her younger days) life in retirement in New York from 1952 until
her death in 1964 at 85.  For example:

 -- She lived in an apartment at 120 E. 73rd Street in New York City
during those last years.

--  She filled her apartment with paintings by her lover, Oskar
Kokoschka, scores of her most famous husband, Gustav Mahler, and
manuscripts of her last last husband, author Franz Werfel.

-- She kept in touch with musical and literary lions of her
generation, such as Thomas Mann, Benjamin Britten , Erich Maria
Remarque, Dimitri Mitropoulos, and Igor Stravinsky.

-- She worked on her autobiography, "And the Bridge is Love," which
she completed in 1960.

--  Leonard Bernstein was instrumental in reviving the reputation of
Gustav Mahler as a great symphonic composer, and in 1962, at the age
of 83, she attended rehearsals of Marler's 8th Symphony by the New
York Philharmonic, conducted by Bernstein.


All of this and more can be found at this page on the "Alma" website linked above:
Alma Mahler: Press Corner: Alma in New York
http://www.alma-mahler.at/engl/presscorner/almaundnewyork_02.html


Additional Information:

Alma Mahler was the subject of a 2001 film called "Bride of the Wind."
 You can find information about it here, including a link to reviews
of the film:
Internet Movie Database: Bride of the Wind
http://imdb.com/title/tt0212827/

American musical satirist (and Harvard mathematics professor) Tom
Lehrer wrote a ditty about Alma that begins as follows:

"The loveliest girl in Vienna 
Was Alma, the smartest as well 
Once you picked her up on your antenna 
You'd never be free of her spell 

"Her lovers were many and varied 
From the day she began her beguine 
There were three famous ones whom she 
married 
And God knows how many between"

Here is a link to the complete lyrics of the song:
Sing365: Tom Lehrer: Alma
http://www.sing365.com/music/lyric.nsf/Alma-lyrics-Tom-Lehrer/DA50884731EAF2F848256A7D00256E43


Search Strategy:

I found the comprehensive "Alma" website by using the following search terms:

alma mahler "new york"
://www.google.com/search?sourceid=navclient&q=alma+mahler+%22new+york%22


I hope and expect that this is the information that you are seeking. 
If anything is unclear, please ask for clarification before rating the
answer.

markj-ga

I find it a little odd that the most comprehensive resource to the
subject is a theatrical site...that being said, I could not find
anything else either and I did not dig into the site....;