The rusted ring is not needed to play through. I have finished the game without it. If anything Dark Souls rewards you with the ring for going off the beaten path and exploring. I honestly went to the crows nest because I was like " i wander if I can get up there"
Also, thinking that Intelligence levels Pyro is you coming into the game with prior conventions. Plus there is a Bonfire at the top of Sens Fortress and that "hidden giant" throwing fire urns does so at intervals. Just keep moving.
Lets be honest, Dark Souls isn't for everyone. It needs a little more dedication and investment than most games. I got all the stuff the negative dude is throwing at Dark Souls without looking it up. I just played, explored and played some more. My first run through was broken as hell, but it only made me roll another toon and better my mistakes.