HELP!! Should I trade in Or not?? please...need advice?

I've only had credit for 6 months. My car is in my grandparents name and i'm trying to put it in my namalfe. Its hard to get financed and I'm wondering if i should trade it in, or should i just stick with the car & pay it off first? I still owe a little more than half on it but less than the blue book. I'm barely 18 & don't much about stuff like this so excuse me if you think this is dumb...i Just need some advice b/c no one here is really helping. please & thank you!
well i"m payin 50 dollars for the car + 150 for me as a driver....thats already 200 just for insurance & my grandpas credit isnt all the great & his interest rate is 16%

NEVER trade your car in to a dealer, they will give you nothing for it.
Sell it yourself privately if you want to get rid of it.
If you do get something new, MAKE SURE you can afford the payment.

Keep it in their name for now. Insurance for someone your age is very high.