I've seen some Expresscard Firewire adapters, but the ones I read up on seemed to lack Vista drivers or have other problems. I never got to finding which, if any, used the Texas Instruments chipset (the right one for reliable audio work). I'll be interested to see the replies too.
 Oops, 54mm -- that's standard bus card form. I was thinking 34mm. Beg pardon. 54mm is a much more popular form, so there should be something available. The SIIG NN-PCM312-S2 has a TI chipset but it's ancient; I've no idea whether there are drivers for modern OSes.
I would contact Scott @ ADK who builds laptops for DAW purposes, and get some opinion with your model if firewire is really feasible path or not. He might say that's not a good idea with your particular model. I would be also willing to buy firewire express card from him, if he can suggest a good one.
I use ADS Tech Pyro 64R2 PCI card with much success with desktop PC motherboards without 1394 port, but never tried laptop firewire even my Toshiba Satellite has TI chip in it. I usually go to USB with PC laptops, which may be the better option for you.