hello Mr. B - welcome to the GMB.
Unfortunately, your pic isn't blowing up large enough to see the pattern clearly - when re-sizing aim to make the first dimension 700 or slightly less and this should give a reasonable image. As you can imagine, there have been countless stemware designs during the C20 and finding a match can sometimes be very time consuming, and fruitless on many occasions.
Possibly the largest of the replacement sites is...... www.replacements.com
(based in the States I believe) - so suggest you start there and if no luck there are others that might be worth looking at.
The above site will also give an indication of prices when buying individual pieces. Best of luck.