I'd say you're in good shape to just continue nurturing the cards you do have. If you did want the other card it would be best to do it quickly so your AAoA doesn't take a huge hit. I have 4 secured cards working for me right now that will be phased out as I get real cards/better credit overall. 3 is the magic number, but 4 seemed to work for me.
Starting Score: 532/564 10/21/12