Right,

so you will need to convert the number to text with a formula. I have a small collection of them, but here is one that should work from my notes.

Substitute in your field name where I have the field [currency field]

var number Value = Round([currency field],0.01);

var text Decimals = "." & Right(ToText(Int(Abs($value) * 100)),2);

var text Thousands = If(Abs($Value)>=1000,ToText(Int(Abs($Value)/1000)));

var text Hundreds=Right(ToText(Int(Abs($Value))),3);

If($Value=0,"$0.00",

IF($Value<0, "-") & "$" & List(",",$Thousands,$Hundreds) & $Decimals)

Let me know how it goes and if I need to test the formula myself.