Many buyers are shying away from short sales and many agents are not showing short sales because of the expected length of time for the lender to approve the sale. This is especially true in Sonoma County where we are still in a declining market. Now that you have your lender approval, I would definitely put your home back on the market and have your agent put in the listing that the bank has approved the sale for your list price. This is much more appealing to a buyer as it pretty much guarantees that the sale will go through. Having completed many short sales this year, I am seeing an increase in the lenders cooperation to get these deals done and avoid foreclosure. Have your agent check the comps to see if your current list price is still appropriate for your area. And once your agent does put your home on the market, they should launch new advertising indicating your recent lender approval.
Good luck - I expect that with your lender approval, and if you are priced right and in good showing condition, you will see another offer soon.