Hi, we don't give valuations usually on here - it's best to look around the net at other pieces to see what the prevailing desire is for a piece. Possibly check on Ebay as well to see if any come up on there.
The owner of the site you link to is a member of the Glass Message Board and I'm sure his identification is correct.
I can't see your pictures very well as they don't enlarge enough and I couldn't see it in the catalogue pages I could find to be able to give you a pattern number, but I am sure it is Chribska.
I have one that is 47cm or 18.5" wide and weighs 2.7kg or 6lb