First off I transposed your data table and renamed the tab to ExchangeRate so I could reference it better (For me, you can change it back with no ill effects)

Secondly I added a second date, which is just the From date from the next entry.

Then in H I added the following code on your test tab

=SUMIFS(INDIRECT("ExchangeRate!"&HLOOKUP($C3,ExchangeRate!$1:$2,2,FALSE)),ExchangeRate!$A:$A,"<="&$A3,ExchangeRate!$B:$B,">="&$A3)
You can mess with it from here and make it flow how you would like to see it...But this is how I imagine I would go about it...

Currency issue - Copy.xlsx