You're not getting security updates anymore for 10.10, so I would say it's not safe any longer, but you can wait for the release of 12.04 and upgrade to that version. 10.10 reached the end of it's lifetime and no one else will be carrying the burden of supporting it.
If there is an option to install an additional graphics card, I would recommend you buy a (new) graphics card. It doesn't have to be top notch or even the newest generation, a low end to midrange model from the last 3 generations with passive cooling will suffice. You will get a nice Unity 3D desktop and with proprietary drivers probably even video acceleration.
If Unity is nothing for you 12.04 will provide the package gnome-fallback-session.