Interest rates HELP

Ok, I found an '01 cobra near my house and after much haggling, got them to come down from the original price of $20,495 to $19,700. I was shown the dealer inventory history on the car, and the dealer purchased it for $19,600. I know they probably gave somebody this much so they would trade it in and buy a new vette. (It is a chevy dealer) Anyways, the dealer got me financing at 11.9% for 60 months. My payments would be around 350 a month he said, problem is when I do the math it comes out to around 300 a month. Heres the math:

I have $5,000 to put down, so $19,700 plus TTL minus the
$5,000 comes out to $16,187 that I have to finance. I multiply that by.119 and get $1,926. Add those two = $18,113 , divide by 60 and I get $301.88 ????

Am I correct in this math?
Thanks for any help

Thanks for the help, guys. Yeah, I know 11.9 is way high, I am going to a bank on tuesday to see if I can do any better. Supposedly, it took a "favor" from the manager's friend to get me that rate.

I will see if I can find anything better.

Thanks for the help you guys, I just got approved from e-loan.com for $20,312 at 7.80%. Much better rate I think. Anyways, that puts my payments on the Cobra at $325 a month, still not sure if I should do that, because I can get myself into a 2003 GT for $287 a month, plus I have a warranty and 15K less miles. What do you think??