How to buy OSx Snow Leopard in Croatia?

Hello,

I have an iMac, late 2008 10.5.8 and want to upgrade to Mavericks. I read on the Internet that I should buy OS X Snow Leopard first.

I tried to purchase OS X Snow Leopard yesterday at apple.us but couldn't get pass checkout since I'm not from US (I'm from Croatia).

I somehow got through IP check yesterday (I cannot do it today) and was connected to US support person (Alex). Very nice man/woman. He pointed me to official Apple resseler (Apcom www.apcom.hr/).

I contacted the support there and they explained that Apple does not offer OS X Snow Leopard in this region.

Now my question Is:

How can one buy OSx Snow Leopard in Croatia?

i.e.

How can one upgrade from 10.5.8 to Mavericks in Croatia?

Thank you!