I went for my first swim today since being back 'in training'.  I've been working consistently with the weight lifting routine four days a week and I feel very strong so I was really interested to see how I felt in the water.  The verdict- even though my cardio system has a ways to go, the improved strength made a remarkable difference.  I did a few 25s and 50s and my times were only barely off what I was doing when I was swimming four days a week pre-pregnancy.  The longer intervals will take some time, but they weren't horrible.  This was exactly the boost I needed to reaffirm all the work I've been putting in.