I loooove your windows in that room. Your house looks great. What is your budget? Depending on what it is, I have a few sources you can look at. On the higher end, take a look at https://www.circalighting.com/ They have a gorgeous selection and timeless designs. Restoration Hardware is another great higher priced store. For something in the middle I like to shop at Pottery Barn or Crate and Barrel for the style home you have. For something that won't break the bank try West Elm, Cost Plus World Market, CB2, or Pier 1. I have a few of my faves for your table below:

Pietro Hanging Shade from Circa Lighting

Lots of little lights, but isn't it pretty? The Clive 6 arm by Crate + Barrel

Fabric Geo Shade fro West Elm

I like "simple" industrial looks. Home Depot "Palermo". $244 31.88"

Is the light a rewired antique? If so, it is a wonderful piece. Looks like 1920’s Art Deco with frosted glass…valuable.

I think you should keep the light, put it on a dimmer and spend your money on a new (old) dining table.

I love that wall color in the dining room. What is it?
I would take a look at a lighting store which carries Craftsman styles. Your dining room is similar and the wall color could be found in a Craftsman home. Then you could add a good-sized rug under the table (4’ wider and 4’ longer than the dining room table when fully extended, if it extends.

You could have a radiator cover built (or buy one) that reaches up to the window trim. It could serve as a sideboard or just hide the rad.
Your moldings are beautiful, too.

First, you have a beautiful home. In locating your fit-it's impotant to remember that just like anything else, a chandelier should represent your own personal style. Don't get caught up in "playing by the rules". Pick something that can enhance your space and works with the way you actually live. The chandelier should be the crowning jewel of the room. The perfect chandelier will tie all of the elements of the space together.