From what I've read, FCP X 10.1 will only utilize two GPUs if they are the same exact card. Two 5770s will probably get you around ~45 seconds on a BruceX test.
Your current config will mostly only help you in Davinci. Probably AE too. The Quadro will be great for AE and Davinci, but I'm not sure if how well it would perform on FCP X 10.1 alone.
I would take out one card at a time and run the BruceX test on each card separately. If the Quadro is anything like my Nvidia GTX 285, it will suck in FCP X 10.1. Apple took away the Nvidia web driver in Mavericks, which caused my 285 to not use OpenGL drivers anymore (I believe that is what happened from what I've read).