wired/wireless

It should be fairly straightforward to add a new wireless router.

It might be easier to replace the current router, however, as you run the risk of overlapping IP subnets.

Yeah, just get a combo wired/wireless router; it will serve as your wireless access point and will bridge your wired and wireless machines. As far as multiple routers go, its fairly straightforward to chain routers, but in most home-user situations, not necessary. In the unlikely event you wind up needing more ethernet (wired) connections than your wired/wireless router provides (usually 4), a simple ethernet switch or hub (sorta like a USB hub, but for ethernet) - slightly cheaper than a router - is often the best way to go.

Thanks all, I guess I will do the new combo router route.