Error when checkout (Currency changed but amount did not changed)

[jakartacube]

Hi,
 
I was just trying to use Paypal in my store. I have two currencies, US$ and IDR(Rp). My default currency is US$. I tried to purchase products in (Rp) and check out, the currency still in Rp for the total amount,
 
 
 
 
but when I chose Paypal as my payment, it moved to Paypal and the total amount changed into US$ but didn't convert the amount into Indonesian Rupiahs (Rp).

 

 
Is there any way to fix this?

 

Or, is there a way to insert notification, like telling the customer to change currency into US$ first before proceed to make payment with Paypal.

 

Please help with detailed instructions.

 

Thank youu...