I'm assuming that you mean Tossa de Mar, since neither I nor Google has heard of Tossa de Mal.
There are no trains to Tossa de Mar.
Are you flying into the 'real' Barcelona Airport (El Prat) or into one of Ryanair's two 'fake' ones (Girona or Reus)?
From Girona (which is the logical airport to fly to, since it's the nearest to Tossa de Mar), there's a bus twice per day:
http://www.sarfa.es/paginas/aeroport_SUD.html
It's about 40km (25 miles) from Girona Airport to Tossa de Mar, so a taxi shouldn't cost too much.
The 'real' Barcelona Airport is about 100km (over 60 miles) from Tossa de Mar, so a taxi is bound to be expensive. (Reus is over twice that distance from Tossa de Mar, so I hope that's not where you're flying to!).
From Barcelona Airport, take a RENFE train for 5 stops, to Arc de Triomf station. (They run every 30 minutes. The journey time is about 30 minutes). Look for the signs to the N�pols Street exit (probably labelled 'C/N�pols'). That brings you out by the bus station ('Estaci� d'Autobusos Barcelona-Nord'). Buses leave from there at 0800, 1000, 1200, 1330, 1500, 1800 and 2030 daily. The journey time to Tossa de Mar is 1 hour 20 minutes.
Chris