I know of one or two pro / semi-pro triathletes / duathletes on this site...I'll see if I can direct them to this thread.
I agree with everything that's gone before - but don't feel discouraged if pro or semi-pro is what you want to do. You've gotta love the sport, be disciplined, and find some means of financial support. There are a number of pros out there who have set up their own business - usually in clothing, coaching or nutrition related to triathlon. Some athletes have done interviews describing their typical daily existence, which make for interesting reading.
It helps if you're accomplished in at least one of the disciplines - which you are! (However, because of the growth of the sport, the present youth membership of the sport are being coached in all three disciplines from a very young age - so watch out!!!!!)
In terms of the volume of training, pro triathletes are probably comparable to pro rowers - and perhaps more.