Best Wireless Broadband modem option?

I have recently purchased myself a shiny new Dell XPS M1330 laptop. One of the options when I was configuring the machine was to include a Wireless Broadband card which was tied to Vodafone, but I already have a USB modem and contract with 3.

I am looking for a more integrated solution for my broadband. Is it possible to purchase the wireless add-on from dell and unlock it? Or is there an ExpressCard product that will work with the M1330 that can use my existing Sim card?

Any advice would be most appreciated.