Woodlawn has had 45 closing on multi-family units in the past year, with prices ranging as low as $100,000 to as high as the mid-$300s. Current active listings range from the below $100 to the high $400s.
Without knowing what type of 2-flat you have (bedrooms/baths, etc.), the location in Woodlawn (remember, a few blocks can make a huge difference in value), and other specifics, it's impossible to know where your building should fall within the market, but it does appear you are on the higher end of the market with your current pricing.
If you are working with a Realtor, she should be able to consult you further.
If you are not, then the problem might very well be in your marketing (or lack thereof) of your property, and that your perception of the building's value is off. I fully support FSBOs, but it can be difficult to separate personal attachment to ones own property when selling, which can lead to inlflated perceived value.
If you have not talked to a Realtor at all during this process, I strongly recommend that you do for this very reason. Many offer complimentary Comparative Market Analysis; you might find that in just talking to one you will figure out what is wrong, and be inspired to utilize their services and expertise.
If you have, and are working with one, it's time to dig down into your current strategy and tweak what is not working, reevaluate the marketing, the price, everything.
Best of luck to you!