Wireless and Wired Router

Question

I currently have a desktop and a laptop connected to a wired router. I need to keep them that way. I am going to be adding another laptop that I would like to use wirelessly. Can I use a wired and wireless router together? If so, what wireless router would be recommended? Or is there some other way to make this work? I need the wireless to go throughout my entire house, upstairs and downstairs.

Thanks.
JA