Hello lorimk40.
The two really aren't comparable. Let me try to explain it to you simply.
Broadband defines the general speed of connectivity. There are 2 main 'buckets' Narrowband (usually refers to connecting via your phoneline using a standard modem. The connection speeds are much slower than the broadband speeds and therefore browsing, downloading and doing anything online is much slower), and Broadband (which usually refers to connecting to the Internet via a DSL modem, cable modem, satellite, fiber optics, etc. where the speeds is tens, if not hundreds of times faster than via narrowband).
The main difference is the bandwidth, which translates into the speed in which data is transferred to and from your computer from the Internet. Depending what country/city you live in, your phone and cable companies probably offer a variety of options to get broadband connectivity.
Without more information it’s a bit difficult to understand your full question, but given your wording I’m guessing you’re thinking of buying a computer and you’re trying to decide whether to go with a wireless card or broadband card.
If that’s the case, this really depends on where you intend to set up the computer, and if you already have a wireless network set up at home (or whatever the location of the computer will be).
If you get a wireless card, that wireless card needs to connect to a wireless router/gateway that is basically ‘serving’ the internet wirelessly.
If you don’t have that set up, you want a broadband card, which will connect via an Ethernet cord to your source of connectivity.
I hope this helps! Let me know if you want more info on anything in particular.
Good luck, Itay.