If this upcoming exam will be your first, I would recommend going ahead and taking it in June. Five weeks is more than enough time to make a serious score improvement. Additionally, SAT scores are reported to college on a composite basis, so you can pick and choose scores across this test in June and the one in October (assuming you decide to take it again). Moreover, two tests is fairly common amongst HS juniors. I would only take it a third time if you KNOW, without a doubt, you'll score better. Never take more than 3 exams.If this won't be your first time, I think more prep time is always better than less. That said, focus on your AP exams and finals, then refocus on the SATs when summertime rolls around. Then do your best in October, with three months of studying under your belt!

the later the better.. i think. you'll have more time to study

The earlier, the better. I'd go with June.