I don’t think Firewire to USB exists, and if it does I’m sure it’ll introduce some extra latency at least, or incompatibility problems at worst.
In other words, don’t buy a Firewire interface if you don’t have a firewire port :p.
You may have a small 4-pin firewire input on your laptop though, for which there are adapters which work fine.
If your laptop has a PCMIA slot, you can get a firewire card for that. Make sure it has a Texas Instruments firewire chip.
will get my self a Firewire card thanks for the help feel like I know nothing, used to use a G4 with Logic 6 and got my self cubase 7 and PC, cubase really looks good but have to get my MR816 CSX working, and get recording and mixing