Ken, stick with the urethane. Spend some time to do the hand sanding to get the last vestiges of the original urethane off. You can stain the whole thing again without a problem if required. Once that dries, put a coat of urethane on and let it dry.
When you sand the urethane, use 220 and sand WITH the grain lightly, not against it. All you are trying to do is remove the dust that settled as the drying occured. Repeat this urethane/220 sand process for every coat you put on. Before you put the last coat on, use very fine wet sandpaper. Last coat goes on, it dries and then you hand rub with 400 steel wool - LIGHTLY. You are looking to remove the dust again and put a nice shine on the finish.
This is just patient, butt-ugly, time-consuming work. When I start to get annoyed that I am doing it, it's usually time to put the sandpaper/steel wool away for the evening. Once again, I have stuck my nose in - Ijust hope it helps.
