Thanks for responding for me.... I can handle it on virtue mart as you recommended... I have chose the currency which I want to use it my site, but the currency is not changed on the site... It has shown that the currency is same as currency on Store Currency...
I did it several times as you said on virtue mart area:

Also I entered the information of product section and I have changed the currency of product as below:

After that, you can see that there wasn't changed currency and also symbol of currency even sales price amount is 99 euro (I want to see there 50000 by Mongolian tugrug)...

And then, I can change the currency from Store Currency module, which is located in the home page of the site...

What is my mistake and what should I do?