My wife had Stereotactic Radio Surgery (aka as Cyberkinife as mentioned by Max) for a non-cancer brain condition last year and if that is an option I'd recommend going for that as the recovery period is fast compared with the alternatives and the side effects are minimal.
As for dealing with such a crappy prognosis ... I'm not sure how any of us cope with that but we seem to. I could give you the ageing hippy advice about accentuating the positive and looking for beauty in nature, but I think the reality is more visceral. Our mental attitude won't prolong or reduce our life expectancy but a negative attitude will mean that time drags out for you and those who love you as you suffer in misery awaiting the inevitable. If you feel depressed or in pain take whatever drugs are available to alleviate the symptoms and help you maintain a good quality of life. Forget the normal social constraints and do whatever you have always wanted to do or revisit places and experiences that you have enjoyed in the past. As my Grandad, a wise old Lancastrian who in his lifetime had fought both cancer and the Nazis, put it to me as a teenager "enjoy yourself while you can son, you're a long time dead!"
I realise this posting is of absolutely no practical use, but I do hope it made you smile
All the best