Sorry you're in this situation. Hate to state the obvious but it being reported on your personal credit already will more than likely be a moot point if you default being you PG'd the loan.
A voluntary surrender is treated virtually the same as a repo on credit reports. If there's any way for you to earn extra money in order to keep it current, I'd look into it. At least you would have some time to try and sell it and look at other options for the remaining balance without taking a massive hit to your credit.
