Splitting manually sucks. It is far less sucky to enable scene detection and recapture . . . if it took an hour before, it will only take an hour this time plus a fresh battery etc. Unless the footage has been taped over or is otherwise unavailable. In that circumstances you have no choice but to split manually.
Then after you have your footage captured with scenes, you can go through the learning curve on the trimmer and subclips and not be under pressure to split up your hourlong capture file : )
IDo you have a cardbus slot on your laptop? If yes, you can get a PCMCIA card with a firewire slot and try that. This is a workaround for older computers that did not come with firewire. The cards I have seen have the big firewire connection so your cord would probably need to be small on the camera end and big on the card end. I've seen these at Best Buy, etc., but they may be less common these days so you might need to look on-line.
By now you have probably finished working your footage. Perhaps a solution for the future if this happens again.