I'm a medical student from Ontario, so I'll try to give you a good idea of what I would tell a patient about snacks pre and post workout. When you are exercising, your body needs glucose (sugar). It gets this from stores in your liver, and once those are used up, from burning fat. This is why some endurance athletes will "carb load" a day before a big event - they are increasing their stored sugars. That's only effective, though, if you have about 12 hours between eating and working out, and only really necessary for endurance events, like a marathon or long bike ride. About an hour before vigorous activity, you can have a light snack, especially if it's been a few hours since a meal or you feel like you need a boost. It doesn't really matter if it's high in protein vs fat vs carbs, but rather that it's healthy. At a glance, these bars seem pretty good (no cholesterol, no trans fat, high fibre), but I would also suggest that you look at your overall intake of fat, protein and carbohydrates throughout the day to make sure that they're balanced. Post workout, the most important thing you can do is hydrate!
Hope that helps,