Hiya
You may find it easier to get the bus.
You will arrive at Terminal 2B, and from there there is a bus right outside which goes in a circle from T1-T2-T3 every few minutes or so.
You need to get that bus round to Terminal 1 and when you arrive go up two floors (two different lifts) then when you exit the terminal you can get one of the following buses.

http://www.hife.es/en/horarios/?max_data=13-09-2015&now_data=26-05-2015&calendario=1&origen=BARCELONA+AEROPORT&destino=TORTOSA&salida=24-06-2015&slttipovuelta=0&inputregreso=&sltnum_billete=1

I used this bus going the other way yesterday and it was a doodle. I do speak spanish however I noticed that most of the bus drivers and staff at airport spoke english to many people.

I hope this helps.
Sarah