The only things that are particularly useful in a preworkout shake are sugar, caffeine, beta alanine, and creatine. A preworkout shake is supposed to give you additional energy to work out with. Having ate about an hour or two before hand also helps as you've got fresh energy to work with as well as no hunger (not to suggest that it's necessary).
- Sugar (or carbs in general) is useful because of how the body prioritizes energy derived from carbs (sugar just happens to deliver that energy faster).
- Caffeine is a nearly omni-present ingredient for preworkout mixes for one simple reason, it works. It stimulates the body and helps to provide mental alertness. Stay below 500 mg daily, but something like 200 mg might be plenty for a preworkout.
- Beta Alanine is a very common ingredient in preworkout mixes, it stimulates the muscles in a unique way (people often report feeling strange at first) and helps to give your best performance. Stick between 0.8-2 grams.
- Creatine is useful as a preworkout and/or postworkout. It helps to increase the production and supply of ATP within the muscles. That additional ATP helps to provide extra energy. Stick between 2-5 grams.
As far as a post workout shake is concerned, you want to avoid fats as that will slow down the absorption of the protein that you're trying to get to your freshly worn out muscles. With that in mind, the most useful things are simply a quick to digest source of protein (whey is the fastest) and creatine.
- Potential sources of protein include Milk, Whey, and Egg Whites. However, fluids will always be absorbed quicker than solids, but Egg Whites are a good option for variety if you want it.
- Creatine is mentioned here again because it is still useful for recovery. You can have it either before, after, or split between pre and post workout.
With those things in mind and based off of your question, here's what I would suggest. Buy or mix your own preworkout mix based on the things I have listed above. As far as sugar goes, a fruit is probably best (a banana or kiwi for example), but sugar is probably the least important of these things honestly. When you make your post workout shake, there really isn't any reason to do more than 30 grams of total protein (not to be confused with the weight of powder) as that's generally close to an optimal amount. I would suggest mixing powder with skim milk. I see that you're also doing multivitamins and fish oil tablets, those can be done at any time and aren't exactly related to building muscle, but they do offer health benefits and continuing to take them at the same time might prove useful for consistency.
Overall, it will be what you eat over the course of a whole day that will determine if you gain weight or lose weight. Muscle is built slowly, 1-2 pounds (.45-.9 kg) of muscle is the ideal amount that you can grow a month. Fat loss is much faster, and fat gain is much faster. If you are overweight, focus on losing a small amount of weight each week .5-1% of your total weight each week should be enough. If you are thin and simply looking to add muscle, stick with 1-2 pounds (.45-.9 kg) gained each month (divide by four for weekly values). You should also be consuming a certain amount of total protein every day according to your body weight (including your postworkout shake across all of your meals and snacks), that amount is either 1-2 grams per kg of bodyweight or .5-.9 grams per pound of bodyweight (going over isn't bad, it just lacks benefits).