6.5% isn't a guaranteed return on the market. I'd consider paying down the HELOC first. However, if you don't have an emergency fund, and you feel you need one, a Roth could satisfy that need. (Just in case you didn't know, you can withdraw your contributions from a Roth IRA at any time)
EDIT: Also, you won't get a tax break for contributing to a Roth: it's taxed up-front. If you're considering a traditional IRA, I would just pay the HELOC first, as you won't have the tax-/penalty-free withdrawals with a traditional (as far as I know).
DOUBLE EDIT: OMG IT'S INSANITY!!!!!!!!!!!!!!