GRE: As of this summer, you can now pay a small fee (I think it's something like $20) to choose which scores to send. If you have the time, I'd recommend studying for a month or two (focus on principles of algebra, arithmetic, and number properties and take several full-length practice tests--space out the practice exams--i usually took one every weekend--take your last practice exam about a week before the GRE). Then retake the exam.
For my first GRE practice test, I scored very low on the quantitative section and had verbal scores in the 90th percentile. I knew going into it math would be my weakness. I ended up signing up for a Kaplan prep course to tackle this problem. I took 7 practice tests, studied about 7 hours a week for 2.5 months. I just took the GRE and ended up increasing my math score 250 points on the old scale (11+ on the new scale). I seriously did not think it was possible for me to do so well on the Quant. section. There is hope--just put in the work.
GPA: My understanding is that graduate admissions committees often heavily weigh undergraduate GPAs. (I wish I had your GPA!) I'd venture to guess that at most schools, a 3.9 GPA will give you some sort of advantage in the admissions process (some a big advantage, others less so). Each school is different though, so if I were you I would retake the GRE just to be safe.
Also, it wouldn't hurt to email the admissions reps and/or faculty at the schools you're most interested in. Ask them which factors matter most in terms of admissions criteria. Ask them if they have a GRE cut-off. Certain English programs don't even look at math scores. Not sure about music, but it's worth asking.