Configuration: Cable Modem w/ DLink DI-524 wireless router. 1 desktop is tethered to the router (ethernet cable), 1 VONAGE router and phone is connected to another router port (ethernet cable). I have a laptop with a DLINK Airplus G card (DWL-G630).
Background: Did not have connectivity issues while in smaller temporary apartment. Moved to a newly constructed house and I get poor reception. Everything is located on the second floor in the middle of the house. Typically we use the laptop on the first floor almost directly below the gear on the second floor. The network connection on the laptop typically shows "Low" or "very Low" signal strength and the connection sometimes drops/disconnects.
Attempted fixes: I purchased a 15dbi Hawking Directional High Gain antenna (HAI15SC), and made several attempts at positioning the antenna. No noticeable changes.
As an aside, our home phones are not in the 2.4GHz spectrum (they are 5.8GHz).
I am considering purchasing a different brand router like a Netgear or another single antenna brand in hopes that I will find a better router product and that I can continue to use the high gain antenna (would not be able to use directional antenna with Linksys. Currently looking at Netgear WGT624 Super G router. Anythoughts before I end up doing the hardware shuffle??

I purchased the Netgear WGT624 Super G router. No noticeable gain (pardon the pun) in range or data rates. Looks like I'm forced to do the hardware shuffle. I have been reading about the new MIMO routers which supposedly have multiple internal antennas that are able to use multiple channels and multiple transmission paths to overcome interference, reflection, etc.
Sounds promising?!?
I have returned the WGT624 and am going to try Netgear's Rangemax WPN824. I still have my standard 802.11g D-link wireless card. I know that this will work with the Netgear Rangemax. However, would it be in my best interest to buy the corresponding Netgear card? I would like to avoid spending the $80 for Netgear's card.

It's very possible that the material/construction of the floor that separates the two floors is blocking/absorbing/reflecting the signal and would hinder any type of connection. I have a DI-624 in my room upstairs that is able to be connected to by two downstairs computers and one upstairs computer. All the connected machines read 90% signal or better, so your wireless devices should not be having a distance issue (unless you have lowered the strength of the antenna signal in any of the configurations). Sometimes the materials used in construction make using wireless devices very difficult if not impossible.

Thanks Chris,
My house is a 2-story modular home. The flooring between each level is "twice as thick" as traditional homes. Each modular piece has its own subfloor and roof framing...result: dividing floor between floor 1 and 2 is twice as thick. I have tried the rangemax and it seems to slightly improve my reception. I have talked to another individual that owns a modular home, and he has the same problem (especially going from floor 2 to the basement). It appears that there is too much stuff/material in the way, which attenuates the signal. Someone else recommended the Netgear WGXB102 range extenders which plugin to outlets.
Reading reviews on that product suggests that they appear to work, but throughput is considerably less than 54MBPS.
The good and the bad....good construction is inversely proportional to wireless reception. In hind sight, I wish I would have run fiber and more cat5 connections throughout the house.
Thanks for the reply!!!
R/ Forever doomed with poor wireless reception