Hi Palme, welcome to iStyles. Credit card payments will be the preferred of payment for international transactions. I'm afraid that Maestro cards cannot be accepted by our credit card payment processor, but do try the checkout with the "PayPal" payment method selected. PayPal in your region might accept Maestro and it might even be possible to link your local bank account to PayPal to make an "echeck" payment.
Telegraphic bank transfers as you've suggested will not be recommended as the bank charges for such transfers typically cost more than the entire order.
The Flowerize design currently ships only from the US warehouse where shipping charges to Germany are estimated to be about $9. The Flowerize design will be available at the Singapore warehouse about one week and a half weeks later and the shipping cost from Singapore is $3. The warehouse availability can be checked at the "warehouse availability" section in each product page, for example
Flowerize iPod nano 2nd Gen Skin