Each graduate program will most likely require some type of standardized test score as a part of your application. There are various providers of preparation courses and books to help you increase your performance on the exams. The CCO offers literature on some of the more common standardized tests as well as help you through the registration process. The easiest ways to find a testing center or to sign up for the test is to google your respective exam and follow the links there.
For standardized preparation courses in the local area, visit the Kaplan Test Preparation Center in South Bend at (574) 272-4135.
While some graduate programs have no preference for the amount of attempts at obtaining an acceptable score, some schools will frown upon taking these exams more than one time so it is best to be as prepared as you can be the first time you take the exams. Make sure to check with each program to which you are applying to see the exam(s) they prefer or need.
Your standardized test score is not the indication of whether or not you will gain acceptance into a graduate program. It is one of the factors but is not the only tool for evaluation that schools use. Most programs will post a range within which their typical entering class scored. Compare yourself to these scores to see how you fit with the program itself. Again, it is only ONE aspect of your application and you should put forth as much effort on the other portions as you do these exams.