You should consider a balance transfer to a new credit card. These cards have an introductory period, up to 18 months, during which you don’t pay any interest on balance transfers, purchases or both. You can transfer the balance from your high interest credit card and pay it off during the zero interest period.
Before you apply, here are a couple of tips. Do not apply for a credit card issued by the bank you already have four accounts with. Banks do not transfer the balances between their own cards. Also do not apply for credit cards several times in a row as it may ruin your credit score. Wait at least two months and only then apply for another credit card. That will lessen the risk of being denied.