If you are presenting a poster and can't or don't want to carry it with you, there is a copying and printing center just a few meters from the conference venue where you can have it printed. The place is called Torculo, located in Praza Mazarelos, 14 (map).
Please note that this is usually a busy place and they might need a few hours to do the job, so it's better to bring it there as soon as possible just in case.