Where can I get Honda CBR600RR battery ?

You can consult a battery store which has all the bike batteries or you can go with the option of buying the battery online. You can go for the batteries available in the link above, but the price would go up as international shipping would be added to the price. The best way out can be asking the Honda dealers to give you the battery being used in their existing superbike lineups, making it much easier than ordering and waiting for the shipment to be delivered.