Is it your entire computer, or just internet?
If just internet, I'd suggest viewing the thread in offline mode and typing a reply by word processing program. You would then be able to paste a post with only a few seconds of internet access (although I don't know what connection speed you're getting.)
If just internet, I'd suggest viewing the thread in offline mode and typing a reply by word processing program. You would then be able to paste a post with only a few seconds of internet access (although I don't know what connection speed you're getting.)