ncprasad has given you good advice.
A higher score will not weaken your application, but the time you spend into preparing for a retake would be much better invested in building extracurricular, entrepreneurial or community involvement experience. Unless you have reason to believe that you were not completely prepared to take the GMAT the first time, you would probably do better to spend time strengthening other aspects of your application.
Moreover, if you guessed on the last 7 math questions and still managed a q49, you should probably count yourself extremely lucky. That may or may not be the case if you take the test again? Of course you may be comfortable with taking the gamble, but why tempt fate?
One final comment - if you are already looking at Anderson and Haas as "safeties" this attitude is very likely going to be discernible in your applications and any subsequent interviews. I wouldn't think it's advisable to approach applications to schools of Anderson and Haas' caliber with this mindset. In any case you would be surprised at how selective both these schools really are.