Most colleges give you the option to superscore. With that piece of information in mind, you can go into the next trial, focusing on CR alone, and not really exerting an effort in the other sections (Just don't let them go below..say..650). Now the real question is, are you willing to put in the effort once more to restudy for Critical Reading alone? Are you willing to hit the vocab lists, and do all the arcane passages, for a chance at a 30 point increase? If your premeditated answer is yes (not the one blinded with initial enthusiasm), then go ahead, take the exam again.