It kind of depends on how good your transcript is. If you got crappy grades, then having a great SAT score might help you, although I know a lot of people who scored horribly (less than 1200) and still got into more than one university. My first score was 1640 and my second score was 1720. Don't expect much of a difference. You'd be surprised at how low most people score on the SAT. A 1530 really isn't bad. I personally hate the SAT and I don't think it does an accurate job of determining a person's intelligence. Neither does the SAT II.
On the other hand, like someone else said, having taken it twice could make you seem more academically determined and whatnot. It's a pain in the ass, but you'll have a better idea of what's on the test. You'll probably score at least 50-100 points higher.
You could also take the ACT, which is WAY easier than the SAT. I mean ridiculously easier.