Hello Eric, I have done a little search and it looks as though Ivo is probably spot on with Ilanit Olemtov Jerusalem. There was a decanter and tumbler set on Etsy which is no-longer on their 'for sale' list but can be seen on Google if you put in Ilanit Glass. It might be worth contacting them to see if the set was sold, and if not, they might contact the seller to ask if they would relist it.
Although Ivo has mentioned that it is cheap glass imported from Italy or France, bear in mind that the value of a made piece is in the pocessing and handwork applied after the glass is melted down, and many of these pieces are quite pricey.
Keep a look out on eBay as well and it could also be worth you contacting the glassworks if possible.
It would still be helpful for us to see a photo of the full shape of the glass and also the pitcher if we are to look out for replacements for you....if they are available, someone here will spot it!!