I have returned from Barcelona last Saturday, and I have to say that I'm still under the feeling that for 7 days I was like Alice in wonderland, but in a very positive and encourging way. Up to now it is the most alive, vivid, beautiful city I have visited and it is an absolute 'personal must' to go back. I have to thank you for all your tips and information, they were great and above all very useful. Some supplementary info: for Roca Village you can also use the Sagales bus company, from Febra i Puig metro station, for 2.45 euros a trip.
Some advice for single girls travelling to Barcelona: as long as you use your good judgement, the people in Barcelona are willing to help, nice, kind and open hearted and willing to share their experiencies, ideas and of course to help you. I've met very kind and nice people there, and therefore I say that the beauty and elegance of this city is also given by the kidness and elegance of its people. Have no reservations and enjoy your trip to Barcelona: You'll never forget it and you'll always want that someday you'll go back there.