I assume you are talking about the month after Barcelona.
I would say in city like Madrid and Barcelona, that won't be a problem. You would be able to find a room just using English.
Out side of those 2, I would say.
-Still try with English to find a flat to share.
http://www.idealista.com/
http://www.loquo.com/
http://www.enalquiler.com/
http://www.fotocasa.es/
-Learn enough basic Spanish to setup an appointment.
-Find some expat group (FB group, InterNations, Meetup ...) in your new city, they are usually helpful and sometime pass around ads.
-Have someone that could setup appointment for you and act as translator.