Multicurrency support, custom currency exchange rate support

It would be good to have possibility to set prices for exact items in shop enabled currencies. As for an example I buy goods in USD from one supplier and in EUR from other but selling all in UAH. So at the present time I have to convert all prices to USD to be able to use native store UAH automatic conversion at frontend.
Also it would be good to have the possibility to set so called "commercial currency exchange rates" which equals "official currency conversion rate" + x%.