It's a brand new D-link DWA-556 PCI express card with 3 antennas (shouldn't that be antennae?)
Actually, there are antennae that are designed specifically for this type of problem. Since you have been to my house, you'll understand that the wireless router is in the upstairs office and the wireless signal gets to the basement home theater.
Initially, my signal was weak. Did the research you are doing and ended up getting some high gain antenna replacements for the Linksys router. Worked a treat (except for streaming video). In fact, the guy across the street mentions that my signal is stronger than his (of course I DID drink out of Darth Vader's cup once). Note that the 3 antennae on the D-Link are probably disappointingly short (Mark can help you understand this, so they don't spew a long/strong signal (again, Mark can help)
Anyhow, Radio Shack can give you some replacements that you could return if they don't yield any remarkable results. Search on the router name and add "increasing signal strength" to see if anyone has solved using antennae as the answer. Cheapest and quickest.
2nd choice is a range extender. Go to Newegg, type in range extender for a search and on "Sort by", choose Best Rating. Pick the price you like.
3rd choice. Powerline networking. Some plugins that turn a wireless into a wired network using the house electrical lines. Newegg again and Netgear seems to be leading the pack. These things don't seem to have any middle ground - fabulous or failure. Never figured Worth a look. Frankly, I'd start here, but I am ranking from least expensive to most expensive.
4th choice. Pay the bucks and wire the house. Sometimes wireless just isn't the answer. No matter how much time you spend polishing a turd, it is still a turd.
OK, my work here is done.
