Have you ever scored below a 159 on your practice tests, 159 and 3.4 can get you into pretty good schools, but a 165 and 3.4 can give you a decent shot at the top 25.
Do you have an engineering degree? I'll trade you my 166 for it.
As has been said, if you're committed to a retake, better be sure you'll do significantly better. I think the engineering will help you, as that tends to be a less-represented major. Another thing that's always an option is getting into the school you can now (and I think tier 2 for sure, maybe some tier 1's, depending on location), and look at transferring up.