What do you want changed? Do you want the title to say "US Dollars" when you clicked $ on the first sheet, and "Euros" when you clicked euros on the first sheet?
If your action filter are working fine, then add in whatever dimension tells you what currency type was clicked so that the second sheet can know what you are looking for.
What you've asked is really hard to answer much beyond that. An actual workbook showing what you have in your data and on the first sheet would really help someone give you a more specific answer.
I think the way you'll want to do this is with an additional worksheet in the second dashboard. That worksheets text value can be driven by your selection in the first worksheet.
This blog post walks you through how to create a title worksheet step by step: How to Create Dynamic Titles for Tableau Dashboards — OneNumber