cosign on Shasha (sp?)'s blog! i love your blog, honey!
honestly, queen nefi-i pretty much think that what you're doing is just fine-it already seems to have given you some progress, if you went from ear length to almost shoulder length.
i would agree with solitude suggested-try to perfect your rollersets, so you can get to the point that you don't have to iron your ends, just the roots.
just make sure you minimize manipulation (pin curls or flexirods instead of wrapping perhaps), treat it gently, Deep condition, and do protein treatments every once in a while since you're using heat.
you're on the right track
sidenote: i'm not relaxed, so i can't pretend to know much about that, but i've heard many shorter haired relaxed ladies say they don't really bother to stretch that long because of styling difficulties. something to consider.