Ok, someone else can help you out more than I can with the diet stuff because I know for a fact other people on this board have experience with vegetarian diets and I have none. I would say the biggest thing is to make sure you have enough protein. This is where most vegetarians have the most trouble. Try and get at least between 0.85-1.25 grams per pound of body weight.
You can go higher if you need to. This shouldn't be too difficult if you're supplementing with protein powder. If you can eat things like eggs, milk and fish on your diet this is even easier. Carbs should not be a problem on a vegetarian diet and at your activity level you shouldn't have trouble burning them off. Figure out how many calories you need per day based on your activity level, get enough protein, figure out how many carbs you eat and fill in the rest of your calories with fats (good vegetarian sources include coconut oil, olive oil, nuts, seeds, etc.).
For workouts if you are a beginner I would probably try something like Starting Strength by Mark Rippetoe or 5/3/1 by Jim Wendler. Again, I feel you need to build muscle to lean out a bit. If fat loss is your main goal, you could try something like 5/3/1 for your main exercises and superset the assistance work. This is a very simple but effective way to build strength. Along with your swimming and running this will burn a lot of calories so make sure you are eating enough.
Also, make sure you are lifting before any of your swimming and running or you can separate them into different times of the day depending on your schedule (morning and afternoon for example). If you are a beginner, pretty much anything you do in the weight room will add muscle to your frame just make sure you are going heavy on your main exercises and eating enough. Also, I think you would be throwing your money away on L-glutamine. Sorry, without knowing more I really can't give you too much detail. What I have just posted is very basic and general.
The biggest thing is to monitor your diet. If you aren't progressing after a few weeks weeks make small changes and reassess after a few weeks. Over time you will figure out what your body responds best to. If you are lifting hard and getting stronger your workouts are fine and you only need to work on your diet. Your diet has more influence on your body composition than your workouts.