I get where you're coming from but I think men are less concerned about the spelling abilities of women. No offence but I think most can forgive a girl grammatical mistakes if she has breasts like ripe summer peaches. Right? Unfortunately for some guys, women are often the opposite. There isn't much point in a guy having a hot set of abs if his written profile makes him out to be as eloquent as a 12 year old.
I think in your case, however, where it isn't so much the lack of effort that prevents you from writing correctly, it's probably worth asking a close friend to help out. Perhaps you can write the basics and spell check it, and then have someone read it and make corrections as required. Trust me, no one expects a perfect essay. In fact, that may freak some women out!
For messages, perhaps you should have some templates prepared for the initial stages so you can just cut and paste parts. You can explain your situation later once you're chatting!