For day to day use of the shell you could try the updated packages in rawhide which allow gnome-shell to run even on hardware without a native 3D driver. I have installed these packages on my 410M which is currently unsupported by the nouveau driver and have found it works quite well, your mileage may vary.
The original post detailing these changes is here: http://lists.fedoraproject.org/pipermail/devel/2011-November/158976.html
To try this you need to do the following as root:
# yum install fedora-release-rawhide
# yum update --enablerepo=rawhide mesa-* cogl gnome-session
Note of course that installing the fedora-release-rawhide package only adds the repo as a potential source of software, it does not mean you are automatically running rawhide. By default it is still disabled which is why the --enablerepo option is needed on the second command as we only want to grab a specific set of packages (and their dependencies).
Asking when you can expect to see the graphics driver in Fedora supporting 3D, and therefore GNOME 3, on an ATI card is a very generic a question. The driver is known to support these things on many ATI cards. I would suggest obtaining the actual model information and checking the appropriate page(s) under the upstream project:
http://dri.freedesktop.org/wiki/Radeon