I would go for something with a simple elegance overall. Black legwear (maybe black tights with a lace pattern to draw off the beautiful lace on the hem of the dress and architectural design of the print), black socks, a black bag. Then I would really bring out the colors of the print with jewelry in colors to match the stained glass. Necrosarium's Vampire Requiem jewelry in either red or blue would be gorgeous for a more Gothic feel that really takes the religious motifs of the stained glass into account. Or you could do more with jewels and actual stained glass with jewelry like this, this, and this for example.
I think you could make it work by doing a sort of memento mori forest themed Classic/Gothic coord. Maybe go with a lacy black blouse and black shoes and legwear. You could add black lace gloves which would do a nice job of combining the gothic and classic elements and you could also do that by incorporating more deer themed elements with an antique look such as this. Then to make sure the gothic look is prominent you could include an undeniably gothic head piece. You could do something with your antlers like this and to make the look even more gothic you could attach a black veil.