You can find an amortization calculator online by just typing in "loan amortization" into google.
I've used this one before for estimates:
Although, there was something I read once upon a time either on here or on
www.bankrate.com about weird clauses that can be put into high interest loans (pre-payment penalty fees, etc). Someone else might know what I'm talking about, but you need to read through your loan contract very carefully.
On another note, a few posts back you asked about which to pay off first... the car loan vs. credit card debts.... Here's my (entirely unprofessional) financial advice based on getting out of debt faster (which is not necessarily in concert with raising your credit scores):
1. Make regular payments on everything, don't ever ever ever be late on anything.
2. Make a spending budget where you're spending less than you're taking in. Stick to it. Make sure you're at the very least making the minimum payments on all your accounts. Ideally you'll have leftover money for debt-paydown.
3. Eliminate any unnecessary "garbage" from your spending. This can include those "credit protection" charges ($25/month on 3-4 cards adds up to a whole lot!) to that Netflix service you're not really using. Or through your budget planning maybe you'll find out you're spending $2000 a year at Starbucks and decide to start brewing from home.
4. Make a debt-payoff schedule starting with the highest interest rate loans first.
5. Work towards rehabilitating your credit score by starting with the collections accounts. Check out the information in the Credit 101 re: PFDs & GW letters.
5. Did I mention to make sure that you're not ever ever late?
After you've rehabbed your scores a bit and gotten out of debt, you should be able to refinance that car loan and get a much lower interest rate.
As far as the car itself... I just want to lend you a little perspective on the vehicle you've just purchased. This isn't meant to be snarky at all but I wanted to point out some facts to you. This is completely independent of the finance rate.
You've just purchased a used 2006 Ford Focus for 16K. If you look up the going rates for a brand new 2007 SE (not sure what you got), invoice is listing them at ~14.9K. There's also a 2500 rebate being offered through Ford. So that would put the price at ~12.4 for a brand new vehicle if you're able to negotiate the price at invoice (and believe me, some people can). To further complicate matters, Fords have pretty crappy resale values because their long-term reliability (in so many words) sucks. Your 16K purchase wasn't worth 16K brand spanking new with 0 miles on it.
So, with all that being said... between the dollar amount you purchased the car for, and the high interest rate that you're paying, you're going to find yourself completely upside down in a year or two when you go to try to re-finance that vehicle (e.g. you will owe alot more than the vehicle is worth). A reputable auto finance company will not finance a vehicle for anything significantly more than that vehicle is worth.
If I had to guess, I'd say that your "friend" made the dealer at least 3-4K off of you, with close to 1K of it going into his own pocket.
Next time you purchase a car, do your homework at Kelly Blue Book, Edmunds,
www.fueleconomy.gov, etc to find out assessments of reliability, resale value, what the car is actually worth, comparisons, etc.
On a more positive note, if you aggressively pay down your debt, you should be able to do so pretty quickly making 100K a year. I helped my friend rehab his financial situation and making 75K a year he's paid down more than 15K in debt in less than 4 months.
Good luck.