Hi there,
Normally a web-site like
segundamano would be the first place to look. However if you don't speak Spanish, this may not be an option..
Maybe you could pop into 1 or 2 English language schools or Irish pubs in Barcelona and find out from ex-pats already living there what the situation is? I'm not 100% sure on this, but there may be a free English language magazine you can pick up in the Irish bars there that has classifieds.
Lastly, try speaking to your work colleagues. I take it some of them were new to the area before working for the company. Incidentally, if there are any vacancies at your new company please publicise them here - there's more than 1 poster here who would be interested in working in Espana.
Good luck..