Quote from Trademark and International Law on Wikipedia:
It is important to note that although there are systems which facilitate the filing, registration or enforcement of trademark rights in more than one jurisdiction on a regional or global basis (e.g. the Madrid and CTM systems, see further below), it is currently not possible to file and obtain a single trademark registration which will automatically apply around the world.
You have the Madrid system or the Community Trade Mark system (of the European Union) or others for securing trademark registrations in different and more than one country. Doing it in more than one country is expensive - you probably know that and decided to not protect your trademark internationally. I would take a look if the company that registered it is in your jurisdiction. If not and you need it desperately, it might in fact be cheaper to buy it (often that's the business: I get mails from asian registrars twice a month that tell me they know someone will buy domain foo but they can register it for me and ...).