Form 8824 is Like-kind exchange, which basically means you treat the new car same way as the old one. Your depreciation trade-in basis is your adjusted basis of the car at the time of trade-in. Look at your 2010 depreciation worksheet under "basis for depreciation", on a standard worksheet it would be 7th column. You will continue to use the same recovery period, this mean if you already took depreciation for the old car in prior years, you will depreciate the new car for the remaining years.
Depreciation allowable at 100% business use depends on the car's adjusted basis and the year you started using it for business. You will have to adjusted it further for the personal/business use. Turbo tax should be able calculate it for you.
So, on the line under Regular Tax do I enter the cost of the new vehicle? or is it a % like 60
What do I enter on the line under AMT?
the numbers are on your 2010 depreciation worksheet. Do you have a copy of your 2010 return?
If you can't find the information maybe it would be easier to treat the old car as sold and the new car as new purchased. The trade in value would be your selling price and the basis for the new car would be the purchase price minus the trade in value.