The beauty of the card is the external RP SMA connector witch can be used to connect a high gain antenna and the fact that it works very well in terms of injection etc.
If you wanted a high powered card you should have gone for the alfa 500mw USB. It has been well documented throughout this forum and the internet that the Alfa 500mW will pick up the most AP's compared to other cards, if that's what you wanted?
I think you can connect it to a special amlipifier to increase the power of the Edimax Ew-7318usg, I'm not sure.
Only problem is that the amplifier is probably twice the price of the Alfa 500mW, if I'm not mistaken
To answer your question... The trick would be to get a powerful external antenna.
You say "Have tested it at my own network"
I say "I'm not sure I understand but Please keep it legal"