If you buy a laptop with wireless capability (I have an IBM Centrino) is must also have a network card in it as well. So you should just be able to connect it to your existing wired network without a problem.

I think he is BS'ing you. Your new laptop will be capable of wireless but you will simply not be using that functionality (for now).

If an when you want to use that functionality you can simply purchase a wireless router from a local store and configure it yourself. You do not need anyone to come and do it for you. Its quite straightforward and you do not need to pay $150 for that.