Someone on either the NextNY list or this list raved about the public
library at Lincoln Center. It's supposed to have very nice desks (i.e.,
quite a bit nicer than your average NYPL), and free wifi too, IIRC.
Details here:
http://www.nextny.org/Offices+and+Co-working#Suggestedlocations and
here: http://www.nypl.org/research/lpa/lpa.html
Only caveat is that you might be working by yourself (unless you can
figure out which NextNY'er it was that works out of there), but given
that you're living in a studio, maybe that wouldn't be too bad! :-)
You might also want to ping the NextNY list about this and see if you
might be able to start cobbling together a UWS co-working or Jelly
group. I'm sure you can't be the only one up there.
HTH,
DR