A wireless access point or bridge is similar to a wireless router only it is not a standalone device. Bridge's are more commonly found in commercial applications such as a large offices, factories, etc. which have an existing wired network. You will see them added in places where wireless access is desirable or needed.

For your situation you could locate a bridge close to your computer but keep in mind that a run of Ethernet cable between it and your wireless router through a crawl space, attic, basement, etc. is required. They also make a device called a range expander which is similar to a bridge but it's link to the wireless router and the computer is completely wireless. You could also relocate the wireless router to a more central location in the house but I'm guessing you have it where it is for a reason.

Here's a couple of links to LinkSys website:

http://www.linksysbycisco.com/US/en/products/Bridges
http://www.linksysbycisco.com/US/en/products/RangeExpanders

Cheers!
Bill