Although high-speed USB 2.0 runs at a higher signaling rate than FireWire 400, typical USBs rarely exceed sustained transfers of 35 MB/s. This is likely due to USB's reliance on the host-processor to manage low-level USB protocol, whereas FireWire automates the same tasks in the interface hardware.
You will be able to use USB inj place of Firewire, you just need to ensure you buy the right cable (its usually referred to as a "mini-USB" cable) - a good idea is to take your camcorder along to the store should you need to purchase any USB cables.
Regarding a laptop, I have a HP laptop that has firewire and USB - I would highly recommend it for £629 (use the checkout code "AW20" to get £20 off at checkout, making the laptop £609)
Supplier is Dixons, link is: click here