<p>CS is tough. This may seem excessive, but if you really do want CMU(which is pretty much #1, from what I know), then you might just want to redo math on GRE. I'm 95% sure that 740 math won't hurt you, but I do remember a professor at Berkeley mentioning something like a 750 cutoff for the point where they ignore GRE score. A GPA boost probably won't do much more, but it can't hurt. It's true though, that your letters of rec will matter very much more , so if at all possible, try to establish your letter writers ASAP and get close to them over the summer and early next semester. Also research would be a solid plus if you can get some done over the summer or even early next semester depending on when application deadlines are. </p>
<p>I can't say with any certainty, but CS seems to be tough given the Fall 2007 admissions post on this board. I'll let someone else make the final assesment, but you have time to fine tune many things, so I would say go for it if you really want to have all the options available to you come next spring.</p>