Are you seeing any results yet? Because it sounds to me like you're basically on the right track. Making sure you get enough calories is one of the most important things when trying to ensure you're burning fat instead of muscle. In order to keep from losing muscle, getting at least 30% of your calories from protein IS important, but people underestimate the power of "good fats." To burn fat, you need to eat fat. So don't try to cut way back in that area. And finally, strength train! Which you're already doing. (The more muscle you build/strengthen, the more fat your body will burn.) Cardio alone, or too much cardio, especially the same type over and over, can actually break down muscles, so try not to do TOO much of that, and make sure to change it up!

Basically, everything you're doing is going in the right direction, so don't fret. Remember to continue challenging yourself with your strength training.

My daughter is training for a competition right now and is only doing cardio on the stair climber with a lot of resistants. She says running shrinks (burns) the muscle. But this is only one component of her program.
Good luck!

Im no good with telling you exactly how many calories you should eat and im no expert. If you want to build muscle you have to eat a surplus so you gain the weight. cardio should be kept to a minimum (according to Jamie eason, youtube or google her, she has a great video on youtube about what she does) In terms of protein a basic rule is around 1 gram of protein per pound of body weight.

If you want to lose body fat % which is what im also doing now, eat a deficit as usual, but up the protein and the strength training so your body is more likely to eat away the fat and preserve the lean muscle as you are using it.

I ope this helps in some way