Hi Robert,
There are various factors that may affect your decision and those should be considered before taking a decision.
These factors are:
1.Time: Do you think that you have sufficient time in your hand to go for another attempt before applying to your dream college
2.Area of Improvement: Kudos to you that you already know what you need to do. But, do you think you can actually improve that area within this given time.
3.Impact:How much impact does your GMAT score has on your overall application profile.
4.Parctice scores: have you been scoring the same score on the practice tests as well or do you think you may end up getting a lower GMAT score.
The above factors may weigh in to your decision but in the end its your decision and he best way to find out is to contact the college admission committee.