How to create campaign dashboard with the selection by currency amount? (and not by gift amount)

With 7.85 you can base dashboards on queries which would get around this problem.  If you are not on this version, research into doing the upgrade.

Good luck!

I tried, unfortunately, if your dashboard is based on query, than system do not provide grand total.

It is true that Dashboard panels based on queries do not give you the total.  However, you can export/copy them into excel and have excel calculate the total for you. If you click on the Properties button in the upper right hand corner of the pane (looks like a hand pointing to a piece of paper) you can copy the Table to the Clipboard.  Then you can paste it into Excel and easily do the calculations.  If that doesn't work for you, you would have to use a report instead of a Dashboard. 

If you only want to see totals for a campaign you do have the summary information section in a campaign query which enables you to calculate total given to a campaign, total number of gifts, constituents etc 

If you want both the total and the breakdown, you could always create two separate panels one for the summary information and one for the breakdown that sit alongside each other.  This way you will not need to export the data, just simply refresh.