Or you can just retake them and recognize that the improvement in your overall GPA will probably be marginal (you can't replace them and there's a diminishing rate of return if you attempt to increase your GPA by adding more classes), but that a person who actually reads your transcript and your personal statement (where you talk up the fact that you retook and aced those courses) will be able to see what happened.
In my opinion the real question is - what is your GPA. If your GPA is above or around a 3 and you want to retake those courses - cool. You're already above the screen out point anyway, so someone is eventually going to read your file. The number probably won't budge much, but you'll have something to point to. If your GPA is closer to a 2 then you are up a creek. Schools do have cut-offs where they auto-deny and averaging Cs with As only gives you Bs which aren't really going to close the gap from a lower GPA. At that point you might have to think about a masters, but before you spend one cent you need to pick up the phone and talk with the cool in detail about your chances. What you have, what you could possibly have, what it would take to consider you etc. There's no reason to spend a dollar on a masters unless you know its the key that opens the door.