Calculating 900 prices

I have 450 prices that have to be calculated...first you have to convert foreign currency into USD and then to add some numbers. After you are done and you have the final number, you will have to calculate an addition percentage to this number so you can come up with another new price. Let's say from the first process you get to the price $50, the second part will be adding 60% which in this example will be $125. So all together 900 prices - first 450 I the way I explained /will tell more in details later/ and second 450 adding percentages to the first 450 prices you will calculate first. I need this done within the next 24 hours!! So bid only if you can start immediately.