Any decent wifi AP will handle the Amigas B connection without degrading the rest of the network, Agami. I've seen $15 TP-Link AP's not even stumble at a b connection thrown at it.
Dude needs to actually know what an SSID and a passphrase is before he goes further - harping about how legacy Amiga's don't have gigabit capable nic's and all the woe is me stuff is overkill and not helping this well meaning fellow.
Guy needs to sit down and figure out his network topology and basics. Figure out what his internet connection is, how it's passed downstream to his machines via a router and switch, and how it goes on as a wifi signal.
It's all basic as a fart in the wind to us, but let's have some patience and work him through this.
AAA - who provides your internet connection, and what type is it? What sort of modem did they give you? What device, if not an ISP provided modem/router combo with inbuilt wifi - are you using to provide wifi?
Are you able to use whatever setup you have to provide wifi internet access to other computers and devices? If so, the basics are all the same.
Do you have a DSL / Cable / Etc. Connection? What router? What wifi box, if not built into the provided broadband modem/router/wifi box? Please explain exactly the type of internet connection you have and all the components in it, hardware wise, and we'll have better luck getting you up and moving.