Yes, you can use an access point. I had a problem with the location of my Slingbox vs. my modem/router. I bought a wireless access point (almost all the networking companies make them) but be sure to check out the reviews on cnet.com before buying. These are very dependent on distance from the router and what is between the router/access point ie walls, electronic devices, bathroom plumbing and the speed of your router and access point etc. I bought a Netgear WNCE3001. It looked pretty cool but performance was dicy. There are also units that use the electrical wiring in your home. The home unit connects with your router and then plugs into the nearest wall socket. The remote unit plugs into a wall socket where ever you need the access point. That seemed to be more like a direct connection to the router.
Whatever you plan to buy, buy it from someone who has a good return policy so if a certain unit doesn't work well for you, return it and try another model/manufacturer. Asking the advice from a knowlegeable sale person is a good idea as they've seen which units have been returned. Hope this helps.