Just curious how do you post wirelessly?
Anyway I think the Macbook already has a express card slot, it is called the Macbook Pro. You can also buy Applecare for laptops cheaply from American sellers on eBay.
I use 3G, Im on the 3 network in Ireland.
Its quite crap, you cant access any website you want just the 'best of the web'.
You cant even go to google but you can go to macrumors.