The PC's and laptop isn't a problem, any wireless router will do for that..
With the IP phone, how are you planning on using it? Do you have a VOIP service through which you will be using the phone? If that is the case, just make sure to get a router that can handle QoS so that you can give the phone packets a higher priority than the data, or there could be issues with calling.
If you are planning on working remotly from home, I am not sure if simply connecting a phone to the router will do the trick. I don't have much knowledge with that, but I know that my old man is on call 24x7 through work, and he has a VOIP phone set up in the basement that he can have his calls routed to rather than the phone at his desk in the office. This phone doesn't connect directly to the router though, there is another piece of hardware between the two that it must connect to in order to work. He is using a Linksys router that is about 6 or more years old...