Advice On Networking Items' Upgrades?

ive asked something like this before, but i have a better idea now what I need and want. If I get a solid answer here, I promise to mention this topic no more.

my list of choices

since i have saved a lot of Amazon balance right now in my account, i will make my next purchase of a network adapter from only Amazon.com. I already bought a 15 dbi rp-sma panel antenna, and a 500mw alfa wireless g adapter, which are hooked up to my windows vista sp2 laptop that has a built in b/g wifi card (cant connect to any networks). right now I get very good connection (about -62 to -65 dbi). My top priority is to maximize the wireless range. I decided on the 500mw alfa adapter as the best adapter based on the top customer ratings (but i now realize "bestselling" is a more suitable choice).

I believe my best bet is to buy the 1000mw alfa g adapter (currently #2). but please advise me on what upgrade item(s) I should buy (antenna, panel, adapter, router, etc.) obviously Ill be upgrading from the current gear (500mw alfa adapter and 15dbi antenna panel). Although theres nothing really wrong with my current set of networking gear, the signal strength could be stronger, and there is always the occasional disconnecting from networks.

from now on, before I buy anything Id like to verify if i should buy them so I dont regret afterwards

tia

P.S.: Ive tried to do my own research before but its very complex. WHY is "Medialink - Wireless G USB Adapter - 802.11g - 54Mbps - Windows 2000 / XP / Vista 32-Bit / Vista 64-Bit Compatible" always #1 bestseller for months (always on top of the linksys wusb600n and alfa 1000mw)?! Does it have a special quality I am overlooking? I checked the dbm rating and i think its not even as good as the alfa's. Im willing to purchase the medialink wireless g adapter instead of the alfa if theres a really convincing reason, but I think theres nothing that sets the medialink apart from the competition.

Also, how can I determine the next version or release of an alfa adapter? Ive contacted their support and got no response, and googled the company "alfa network" and see no answers there. You see, I hate to buy the 1000mw adapter only to have a, lets say, 2000mw adapter be released on Amazon a week later. But if the next model is like 1 year later, then I dont mind buying the current model now.

please advise. I cant decide.

The Medialink wireless G is pretty cheap, I suspect that is by far the only reason it is "bestselling."
Transmit power is only half the battle. Instead of upgrading your adapter I think I would construct a better "reflector" for your antenna.