Connecting a desktop PC to a wireless router?

Hey guys, my wife and I are about to buy a new home, and the cable internet cable running into the home goes in our bedroom, but we are putting the desktop PC's in different rooms. So I am thinking of putting the modem in the bedroom and the wireless router there with it, then hooking up the two desktops in different rooms that we want them in but I have no easy way to route an ethernet cable to them.

Is there a way to connect the desktop PC's to the wireless router for internet/gaming use? I figured I could get a PCI WiFi card? But I'm not sure if this would actually work, and if the performance would be worth the money.

Is there any other way around this? Anybody have experience with this? I'm not sure if there is a way I could run ethernet cables thru walls, in crawlspace, etc, and up into the rooms with the PC's or not.

Does anyone have any experience with this? I've always had easy access to just plug the ethernet cable into my PC, this is the first time I would not have that option. Would it be wortht he money to have my home professionally wired for cable/satellite/ethernet throughout the home? How much money would this run to have it done right on an existing home?

Thanks for the help!