I'm close to the same boat. I bought my bike and aero bars last Aug. Not all clip on aero bars will fit all bikes so I can't say for sure if they're going to fit. Most aero bars have a couple of clamps that are tightened by allen keys. Make sure they're good and tight or they can slip while you're riding. Move them around until you feel that they are in a comfortable spot for you. It taking me a long time to feel comfortable with them. I can go 40 minutes in aero position now but it's not painless.
If you want to get more specific info on fit of the aero bars, go to beginnertriathlete.com and ask in their forums. There are a lot of knowledgeable people there.
Swimming is the hardest thing to learn. I swam over the winter and through the spring 2 - 3 times a week and I'm just starting to feel like I've got some kind of good technique. There's a lot of technique to swimming so it's a good idea to surf youtube, buy a dvd, take classes, and just swim a lot working on technique each time you swim.