eXDee: The v8 is a slight improvement, but its 1T1R 20mhz wireless N and a similar antenna design, in english this means that it's only 65Mbps, which isn't a huge improvement over Wireless G's 54Mbps

802.11g has an overhead of ~50 % so the maximum data throughput of a 54mbit G connection is around 26mbits
802.11n has an overhead of ~40 % so the maximum data throughput of a 65mbit N connectiion is around 39mbits

I agree that you should upgrade to an 802.11n dual chain router. TP-Link are my favourite and they make routers which allow you to replace the antennas with bigger ones.

Some things you may want to investigate
 - Channel: force set your router to use a specific channel. You can use netstumbler (windows xp) or inSSIDer (vista/7) to scan for wireless networks, see the signal strengths and set your router to a channel at least 3 away preferably use 1,6,11) from your neighbours routers.

 - Antenna extension cable: You will loose 3db of signal when you extend the cable away from the card so an 8dbi antenna only becomes a 5dbi when you have a 1m cable between it and the card in the computer. -However- your signal gain may be more than 3db by having the antenna up higher, where less furniture or physical objects are in the path between the computer and router.

 - Move the client radio: Even better than using an antenna cable is to move the client radio higher, so the distance between the antenna and the radio is less. This is accomplished by
a. moving your router higher with longer network / power cables
b. moving your client radio higher with a usb cable (you can get high powered USB sticks with external antenna connectors on trademe, and usb extension cables - TP-Link make good usb dongles)
c. A combination of a usb extension cable + usb dongle + external antenna directly attached to the dongle

- The wifi windsurfer: This is a genius solution and works well. Basically you print this template here http://www.freeantennas.com/projects/template2/ and cover it with tin foil. Put it over your wifi antenna (click the picture to enlarge it) and it turns it into a parabolic dish. You may need to stack two on top of each other if you are using a large (tall) high gain antenna. They work by capturing radio waves that would normally travel either side past the antenna, and bounce them back into the antenna to strengthen the signal. They also focus the output signal of the antenna and "throw" it into the direction of your router.
Legal note: When adding larger antennas - your limited to 4 watts EIRP so with a typical wifi client radio with 20db of output power you are limited to a 16 dbi antenna. Your 6 dbi antenna + the 9dbi gain from the wind surfer will make it a 15dbi and you will be just below the legal power limit. You can put one on your router and one on the client radio for extra happiness.

 - HomePlug adaptors.
These are my favourite trick that i keep up my sleeve. Many houses that I encounter have a metal contents within the walls - this can be for various reasons and building trends over the years. It may not be concrete, but it can effectivley create a faraday cage.

Homeplug units plug into your electrical wall outlet just like a wall-wart transformer. They have a network plug which you connect one to your router, and the other unit can connect to a wireless access point to offer another "base" for wireless devices to connect to, or to a computer, switch or other networked device at the other end of the house.
The homeplugs use the electrical mains wiring between them to send the network data at high frequency using the power lines within the walls. They have limited range, but they are great for getting broadband out to a garage, sleepout or to the other end of a house when we cannot run a cable thru the attic.
Again TP-Link make a good homeplug and they are priced at about $100 for a pair.


Typically in a similar situation as yours for our rural clients with large houses, we install a broadband router at one end of the house, and use homeplugs with another router/AP at the other end of the house giving them extended coverage.