All routers and hubs can be "daisy-chained". All of the wireless access points you can buy will have an ethernet jack and will connect to your existing hubs/routers. You don't need to replace the one you've got.

The only thing you might have to do is make sure you're using the right kind of cable for the connection: either straight-thru or crossover, depending on the port configurations. Many routers have a crossover switch, or can auto-detect the need for crossover and do it automatically, so that shouldn't be a problem.