Ok guys, thanks for responding, but I still don't know which filter would be right. In my opinion Aquael is better and looks better than Aquaclear .
I found it on ebay. Aquael Versamax FZ - 3 Hang On External Aquarium Fish Tank Filter | eBay . In Poland this firm is said to be very reliable and everyone recommend it, moreover their filters are commonly available.
Which will be ok(FZN-2 or FZN-3)? I know that prefilter will reduce flow a bit, so I can't decide. Won't the FZN-3 be too strong? I rather don't want to have a river in my aquarium