I think @Llewelyn A. hit all the nails on the head. The Brooklyn market is killer and there is no substitute for that. Think of it this way.... you managed to purchase a piece of the greatest city in the world. Not a lot of people can say that and even less can manage to do what you did. DON'T give it up! You also have a phenomenal interest rate!
My dad gave me a great piece of advice about real estate: If you sold your property now, could you buy it back tomorrow for the same price? The answer in most cases in NYC is no. Your concern is holding it. It sounds like the answer to this is improving your cashflow. That would alleviate your concern of holding the property. I would try the following (or some combination thereof):
1. Rent out your apartment for top dollar and move into a cheaper living situation. Your concerns regarding the finishes are warranted. However, if you were to list the apartment with a reputable broker/agency and obtain an exceptional security deposit, you should in essence be "okay."
2. If you have extra $ to invest, invest in a high-cap deal OOS that way your current situation may improve.
Either way the key to improving your situation is increasing cashflow. Don't sell your brownstone unless you face a dire situation.