Are these your pictures or vendor pictures? Do you have it in hand?
So, what is the garnet, 3 carats or a little more? You have 18k gold and diamonds. I'm sure the diamonds are I1 clarity or so. But Brick and Mortar retail not out of the ball park. Depends on the retailer.
Ok. Then I don't think the price was out of line for full blown retail.
Now it is just a matter if you like the ring.
Very pretty. Good size, attractive colour. Considering gold prices right now and labour costs for setting all those small diamonds, the setting is the bigger chunk of that price tag. In any case it doesn't sound unreasonable, especially for a brand new piece. Enjoy!