No, nobody can help you. (I think that answers your question).
The reason being is currency is like stock and the rate exchange changes significantly through out any given day using the
Foriegn Exchange Market[
^]
So there is no way you can design an application that would correctly convert currencies without calling out to a service that is checking the current exchange rate.
You could potentially cache some rates on the local system and use those while the system is offline, but it would need to get online first to get the rates to cache them and you would want to inform the user how stale the data is (10 min, 10 hours, 10 days etc.)