500mw Amplifier or Stronger antenna for Bridge?

Hello.
I just have some questions about the best possible way to set up
This particular wireless bridge.

I currently have a homemade cantenna, connected to my Alfa 500mw b/g USB adapter getting a "good" wireless B signal from the AP approximately .6 miles away.I used an old Linksys B W.Router to share the connection out of the LAN port on my main PC.The problem was If i would turn off the Computer is was no longer shared.

Purchased a WRT54GL along with a 5' pigtail and flashed DD-WRT in hopes to create an outdoor wireless bridge using the cantenna but learned that even set to 231mw of power the signal quality is only 12%.

What would be better to boost the signal?
A hyperlink 500mw amp 500 mW 2.4 GHz 802.11g Outdoor WiFi Amplifier - HA2401G-500
or
A 24dbi Grid antenna like so Pacific Wireless 2.4GHz Die Cast Grid Dish, 24dBi - N Female Connector
Price is not a concern.
Thanks.

1) The benefits of an antenna work in both directions, an amp works in one direction.

2) A high gain antenna will confine your link to a narrow path, reducing interference to and from your link.

3) an amp with a low gain antenna will splatter RF all over the neighborhood. The WiFi equivalent of the jerk with BOOMP BOOMP BOOMP coming out of his car at 3 AM.

4) Consider the benefits of Ubiquiti Bullets for a long link. Designed to handle just this task. If you like Bullets, 15 db yagi or patch antennas will give narrow beamwidth and not look like something from a SciFi movie growing on your roof.

Haha.
Defiantly don't want to be the neighborhood WiFi Douche bag.

Yeah I was leaning towards the trying the antenna first Since the original method with the Cantenna used 15' of LMR-200 compared to the 5' ft for the outdoor Bridge Method.Considerably more efficient.
It thought this would help despite the routers TX.Nope.
But I like the Yagi antennas, and they are cheaper aswell.
(I said price was no matter but thats because Both of those were going for the same on ebay)
The bullets look nice aswell.
Im going to try the antenna initially, then if its a fail I will try the bullet.
Thanks for the Wisdom.

Here the link to a RF cable attenuation Calculator thats really neat.
Attenuation & Power Handling Calculator

the calculator you need:

Support :: Calculations :: System Operating Margin :: Terabeam Wireless