Um I think you are a bit confused.
A Desktop Environment contains many parts, including a file manager, a window manager (manages windows :0), login manager, Desktop Manager, etc...
GNOME is an example of a Desktop Environment. It uses the Nautilus File Manager, the Metacity Window Manager, the GDM login manager, and other parts. GNOME is the default in Celena.
Beryl is another Desktop Environment. It can use any file manager or login manager, but it uses the Emerald Window Manager and the Beryl Desktop Manager. Beryl needs a 3D capable card with 3D capable drivers, and comes as an extra in Celena.
Emerald themes, are well, themes for the Emerald 3D window manager. They are not addons to GNOME or anything like that.
And to answer your question, your machine should run Beryl great, but you may need to install some drivers first. First, try beryl. If it doesn't work well, then: go to MintMenu-Administration-Envy and when the window pops up, choose your type of card and install the drivers.