Check with your agent to see a trending analysis of the sold price for homes in the neighborhood where your investment home is located. You need to determine--just as Jeremy alluded to earlier (with his "1% per month" comment)--whether the prices are continuing to march downward and by how much. You also need to be strategic about ordering appraisals--especially as more time passes, because you may have to disclose the results of the latest appraisal.
Keep in mind that the longer you wait--especially in a market where the current market value is declining steadily--the less you'll receive (if you opt to sell in this market). Instead of flipping that property to a retail buyer, as an investor myself I think it might be better for you to rent the property, and hold it or flip that rental to another investor. The property probably will sell for a higher price if it were flipped as a rental.