When we were there in 2003, the game was played in the small stadium used by Locomotiv and Dynamo. It has a capacity of about 25000 all seated.
There are two far bigger stadiums in Tbilisi, the National Stadium which holds about 55000 and the old Dynamo Tbilisi Stadium which then was nearly delapidated, although the day after our game we went there to see a rugby international between Georgia and Romania and there was about 60000 at it.
I reckon they will again use the smaller stadium as I cannot the game attracting a big enough attendance. Soccer is not the most popular sport in Georgia.