driveshaft on 190e-16v

I've started experiencing some heavy vibration between 55 and 85mph. I know it's not wheel balancing. I took it to a good mechanic i know, and who knows the car. He says the driveshaft needs replacing. The area by the u-joint where the two shafts meet is where the problem is and it's not a piece that can be purchased for example the bearing. I thought at first it might be such or even the rubber rings that bolt on the front and rear of the shaft.
While driving the car under throttle, or upon releasing it, the car seems to slightly float to one side (scary in the rain).
The car also sat (did receive courtesy start-ups) for a year while I was away with the military, however the problem already existed before.
So, any ideas my good fellas? I am somewhat reluctant to go out and purchase a new driveshaft, $$$ wise (not that she's not worth it )
Thanks everyone, as always I am greatfully appreciative of the time taken.

-Adam