There have been several threads befre about weight training for swimmers,
most of that applies to breaststroke.The important things to be sure to include(IMO) are as follows:
Since the insweep is so important I think it is important to do some pulley work that duplicates this motion.
Since leg strength is vital,squats and leg extensions are good.
For leg endurance I like spinning.
Core strength is needed so I do work on the stability ball,especially crunches and back extensions
For explosive leg strength I do vertical jumps in deep water(I used to do them on dry land but my joints got old.)
Breaststroke uses the biceps more than the other strokes so curls are good.
Since all swimmers run the risk of shoulder problems rotator cuff exercises are vital.
Since power is important I recommend high weight/low rep work( except for the spinning and the rotator cuff exercises.)
The main idea is to use the weight to duplicate the swimming motions.The important exception to this is DON'T do leg extensions with you foot turned out(as in the kick) as that puts too much strain on the knees.