Converter prices at the rate of $ to hryvnia Drupal 7

Converter prices at the rate of $ to UAH Drupal 7:

I'm interested in the following:
Shop - Text hidden
Prices on the website are indicated in UAH, which I need:
To put prices in $ in the admin site, for each product, indicated the rate for example 1$=26 g and the prices on the site for the client are displayed in hryvnia. Changing the course every day, prices for customers change, and are displayed in hryvnia! Now the rate jumps and for each product to change prices for a very long time!