I believe you're going to have to purchase a new
tank system. I don't think you can just by a glass shell for your Evod
tank.
Look into the Kanger Aerotank if you like Kanger products. It's available both in a standard and mini version. These have air control rings on the base of the tank which improves the draw intake and performance.

Kanger Aerotank
There are also the Kanger Protank 2 and Protank 3, also available in standard and mini versions. No aircontrol on these. Protank 2 has a single bottom coil and the Protank 3 has dual bottom coils.
All of the above use pyrex glass.
Edit: Correction. Kanger does make a
glass Evod. It uses the same dual coils as protank3, aerotank, evod 2, and T3D .