Everything depends upon how fast you want to run and how many miles you log between now and then; that said, a 50K really isn't all that much further than a full marathon. Last April I started running again after a "six to eight month layoff sitting in front of a computer for long hours", and effectively went from the couch to running 33 miles (split into six legs) in last September's 15th installment of Reach the Beach - New Hampshire, and by virtue of the fact that I had concentrated solely on "Long Slow Distance" (aka. LSD), I really had no problem with the event (I actually got faster as the legs and miles wore on).
Were I coaching you, I would encourage you to ramp your mileage up into the 200+ mile per month realm, and after you've been able to do that for at least three months, I'd say running the 50K would be fairly easy. If you can hit the 200+ threshold six months before your planned event, so much the better, as you'll be even faster.