Wow. That is a pretty absurd interest rate. Have you asked them to reduce it? Call and tell them you have been making good faith payments. But you cannot and are not able to pay that interest rate. Mention that high of a rate will force you to default. The don't want you to default, they might...
You can lower your amount/percentage on a CC by talking to them. They won't let you settle on 50c to the $1 unless you default around 120/150/180 days. At that point your credit is in the shitter for a few years.
It hardly seems worth it over $12k, maybe if you can jack six figures...
You can daytrade with $10k cash. However the 3 day settlement time will severely cramp how many trades you will be able to do per week. Having a margin lets you bypass the 3 day settlement time, but requires $25k.