Welcome to the forum Francine! I'm sure we can help you get to where you want to be.
For your height and age you sound like you're at the perfect weight so the fat loss you're talking about should be minimal. If you combine cardio with weight training you will you achieve your goals efficiently, but as you increase your muscle definition your total weight may rise (as muscle weighs a lot more than fat.)
You mention wanting to increase your butt and thighs, if you incorporate a variety of squats and lunges into your workout they will help with those areas. For tightening the mid section I've found Pilates core exercises can work wonders, also I find swimming helps.
As for protein, I have mine immediately after I work out but there is varied opinion. If you're trying to build muscle I would suggest after a session. As for food a healthy balanced diet will bring you the best results, try for lots of veggies, a few fruits, good lean protein and not too many carbs (always wholegrain) with some low fat dairy and a good multivitamin, lots of water, and variety.
If you enjoy non-gym based work outs then I suggest incorporating them, if you don't enjoy what you're doing (at least most of time!) you'll be less likely to keep it up. If your gym offers classes you might enjoy some of them? It's always worth trying something once!
All the best of luck, any problems you have or questions that pop up, share and the knowledge base here will always help