What do you think my antique piano's value is?

Its value is more of that of a piece of antique furniture than as a musical instrument. It is not a particularly sought after manufacturer. While the case sounds as if it is in great condition you did not mention if the soundboard is in good shape. Many of these older pianos may look great on the outside but inside the soundboard is often cracked or warped making it unable to be tuned correctly. Often times there is damage to the action requiring extensive repairs that could be more than the value of the instrument. You best bet is to have it inspected for damage by a local piano tuner and then have it appraised by both an antique piano dealer and an antique furniture shop.