Gallotti & Radice could be of help
The first and still most innovative glass furniture company based in Milan - I am agent for part of the UK and know they will do a similar table to the one you bought, if it is in fact not the same (they have been going since the 1940s)
http://www.gallottiradice.it/ - email them and they will email you back with the nearest stockist - they won't sell direct as that cuts out the agents
If you want something made exactly the same, I have a company in Liverpool that makes all glass furniture using UV seal process, it is custom made and prices are very high
Most glass furniture uses float glass / amorphous silicon dioxide (SiO2) with the green tint, more expensive is lead or flint glass which is clear and is more in demand these days as it gives a crystal effect
In any case you should be able to get something very similar
Can you post a picture of the ones you have, I may be able to ID them, or one of my Milan companies may be able to help