you can't make the group footer for a 'higher' group display for a lower group, but you can probably code for all the value in higher group to appear in the lower (provided that they are straight aggregate values or values that are known by that time in the report). What I mean, is by a simple aggregate is COUNT or SUM where all values are included. If there are any conditional sums occurring, this method won't work. As this goes to the second part of the statement, values that are known. CR is basically reading the records, so if you are looking for a value that occurs after the lower group but inside the higher group (date in this case) that you want displayed on the lower group's footer(currency group) and you can't get this value by an aggregate, then you can't code for it in the group footer.
You will probably need to change the grouping value on the aggregate to use the 'date' group, as CR will be default assign the 'currency code' group to an aggregate that is to be displayed in the 'currency code' footer.
Hope it isn't to confusing.