Remember that Capoeira is both a martial practice and an art! It is rooted in fighting and in dance. Turn out, rotation and flexiblity in the hips and such are best gained through the exercises taught while standing at the ballet barre!
At The Ohio State University the martial art is taught under the auspices of the dance department, and this makes sense.
My suggestion is to take a ballet class. not only will exercises like Rond de jambe, which is designed to aid turn out, and plie assist in hip flexibilty, it will also strengthen your core, teach you proper alignment for jumps which in turn will assist in landing jumping kicks and other more acrobatic aspects of the marital art, and it will give you flexiblity in your back.
You will also be instructed on how to spot your turns which EXTREMELY valuable! See the documentary on fighting in Blade Trinity and you will hear and see Jessica Biel talking about her spinning kicks and how she couldn't master them until her coach, who remembered that she was an active ballet dancer, told her to "spot" the kick. From the standpoint of both a martial artist and a dancer, her spinning kicks are now flawless.
Just because you are flexible does not mean you are flexible correctly. The superfical muscle may be flexible but you may be doing damage to the connective tissue because you have not learned proper alignment. Someone who can do a sloppy split for instance, can indeed do a split. HOWEVER when that individual learns to do a split properly, they may notice that the depth in the split that they thought they had is gone! In turn doing the split incorrectly will do quite a bit of damage, causing long term complications.
Consider the taking of ballet as a conditioning regime for capoeira, and you will be amazed at the fluidity, speed, balance, strength, AND flexibilty that you will gain!