In regards to a wireless card and price:
You do not need to spend alot of money for a wireless card. 100.00 is just crazy for me to see the stores selling to people. Just get yourself a G card for now, or if you just need the newest get a N card. N cards are expensive and can't be used as of now to full potential. If you have the older B systems in your network you are better off getting backwards compatible G cards for now and they are cheap. I wouldn't pay more than 40 dollars for one that is on sale. They will accommodate your older devices and give you the 56 mps you desire. That's overkill for the ISP's intended speeds if your one of us normal people anyway. Speed is your delivered signal and what you do with it.
PS. Remember that if you do have the older B devices hooked up to your G system, the system WILL revert to a lower speed on ALL devices to accommodate the older devices. This goes for the new N systems as well as far as I can see. ie. N cards: can't use all of it, G cards: still can't use all of the potential (but best buy), B cards: A speed stopper.