If you want to stay with canister filters, try upgrading your rena filstar to the x2 or x3 model (just more room for more media). If you would like another canister filter brand, try fluval or eheim.
I have heard from lots of people that they really enjoy the hang-on-back filters that use a bio-wheel, as the extended contact time of the bacteria with oxygen allows for much more to grow, thus giving better biological filtration. They are also much easier to clean than canister filters.
I apologize that I am unsure what companies will ship overseas, but I'm pretty sure that Ehiem is a German brand. I don't know if you speak or read German, but the krauts make some pretty good equipment for fish care, so you might be able to find some German-based websites that will ship to you.
30 gallon tank with firemouths, serpae tetras, and paleatus corycats. Plants are vallisneria, anubias sp., Java Fern, and pennywort (I think).