I don't know which distance you are training for but from your words, it appears as though your run is strong so no gross improvement there. With swimming being your weakness, I think you should be swimming longer distances. I think you should not be so concern with swimming a 50 on 1:30 but more of distance starting with 150 or 200 pyramids. As for the biking, trifuel.com has some good and intensive workouts on the training pages.