COD is not available, as far as I know, unless you can figure out how to configure using the
real-time shipping plug-in for either UPS or the mail to collect funds (FedEx doesn't do COD) for you....and then you will need to re-configure your transactional base to be more like a "downloads" site, basically authorizing a transaction (and creating a transaction number and shipping order) but somehow not processing payment......dunno on that one.....maybe someone else has done this and can adivse specifically.
If you use PayPal, funds are automatically converted, and the internet "defaulted" currency is the USD or the Euro. Even if you do not use PayPal, and use a Merchant Account with Gateway, funds are automatically converted prior to deposit for you (as they must be finally processed by your bank), so despite your preference for 'display' it is really a moot issue.