I'm surprised you couldn't get it easily rented in V. Can you tell me any details about how much you were looking for/size of the place? It should give you a good return, so maybe it's worth reconsidering selling. I'd imagine you'll lose anything you made in charges after just a year of owning it.
PestiEst is a free magazine over here that you can advertise in. It costs a bit. I'm not sure how much though. You could also try budapestsun.com, which is read by a lot of English speaking people in Budapest. They're both available in bars/hotels, etc. here, so if you're over, just keep an eye out for them..