Should pat myself on the back there. $6.60 was a reasonably good guess.
Thanks to that marvel of modern technology (Google) I have found that the exchange rate was 2.60 Real to the dollar on January 29th. On that date it looks like the nickel price was about $6.70.
Current exchange rate is 3.055 Real to the dollar and current nickel price is $6.47 per pound.