Good luck on your GMAT! As for the IELTS, out of all the tests I've prepared candidates for, that one is the worst. Trick questions with more than tricky answers. Congrats on your scores, btw! Though from your writing I can see that you are more than competent at English, so it's well deserved. Oh yeah, and just because someone is paying an arm and a leg for private tutors doesn't guarantee a thing. I know, I've had clients "trying so hard" without wanting to lift a finger, let alone finish reading a sentence. In this regard, if you know what you want, and you really want it, you can probably prepare much better on your own.
Still, I keep my fingers crossed, just in case. You might need it taking a Halloween exam, after all!