Sorry to hear that you were denied for the Capital One Card. Are you trying to rebuild or establish credit? I believe that my credit score was a little lower than yours when I applied and I was approved. Do you have any idea why you were denied?
Whatever it was, don’t be discouraged, there are plenty of secured cards out there. Amy mentioned a couple of good choices. Other banks that offer secured cards: Bank of America, Citi, Wells Fargo.
You should call Capital One to ask why this happened. Explain them your situation, maybe they’ll reconsider.