You need something called a 'wireless access point'. There are lots of really good ones around. Basically you just plug it into your wired network and it copies everything from wireless to wireful and vice versa intelligently. (It's a ‘bridge’.). Ask around if you want recommendations for access points. I have several myself and a router that has no wireless at all in it. You can have several access points (WAPs) if needed, and park each wherever you want, for best coverage. That is one great thing about wireless access points - you can locate them in the best place for coverage, and no need then for the kit to be near where the dsl line enters the house.
I use ZyXEL access points which are pretty old but good.
