Your E-junkie pricing currency must match the basis currency of your payment processor account, whether the latter is Google, PayPal, etc. I.e., you would need to find some way of basing your Google Checkout account in USD, in order to have E-junkie prices also listed in USD.
BTW, I do know that with PayPal (and I think Google as well?), regardless of your cart pricing currency, any buyer worldwide can still pay in their native currency; PayPal will simply tender their payment and do the currency exchange automatically.