setting up a router

Sure you can. Setup the router with your computer wired to it. Move your computer to another location in your house. Connect your computer to your router via wireless.

Sure. Do the initial setup on the route via a wired ethernet connection (especially if you're going to update the firmware). Once you have it configured working with a wired connection, unplug the ethernet cable and try the wireless. If that works, you can move the computer anywhere within range. The rule of thumb is that wireless will easily go through one wall, has some problems with two walls, and is difficult to impossible with three or more walls. Open doorways, windows, and hallways are a big help. Aluminum foil back insulation in the walls will totally block the signal. See the FAQ at: