Yes, you're right, it's Eastlake ca. 1890. It looks to be walnut, stripped of its finish. I think you're right about the marble top. It would be quite easy to get a new piece of marble cut (with the appropriate beveled edging) to match your piece, just go to a granite/marble/quartz counter top business and have them cut you a piece, then just lay it on top. Before that, refinish the piece with a walnut finish.
Now you're ready to sell, though I don't suspect you'd get much more than $250 for it. However, by the time you've restored the plant stand to its former beauty, you'll probably just want to keep it. I know I would!!