In your case, a prep course might be the correct choice. From what I gather, Manhattan is a solid option. There are certainly other choices available, some of which could be just as good or even better. See the link below and do some research to determine which program provides the best fit for you.http://gmatclub.com/reviews/?fl=menu
As nktdotgupta mentioned, learn more about the content on the GMAT before making a decision. Good luck!