@pyshokitty
http://site.microcom.us/NMP-8602-Datasheet_09122005.pdf
this is the link to the specs of the seno card. You said that you had a CM9 which is perfectly fine. Just try tweaking the settings or modding your router. Remember it is a two lane highway, you cannot blame your wifi card for everything!!! And for range @ feet. It is difficult to say how much improvement will it give you but @400mW it is higher than what normal routers can give you (the highest a normal router can go is 251mW).....even the placement and obstruction to the signals can matter a lot....and all these phones and ovens......
@LifeVirusZERO
wireless is good but can never work better that wireed.....thats a proven FACT. If your laptop has interference like phones ovens......and even wall between your router.....all can affect the speed.....it has very little to do with the card....if you still feel it is lagging then go ahead and buy a senao or some atheros chipset based card......
@newfiejudd
you need mini-pci express for newer laptops....means your need 5006EX chipset based cards.....check the specs thourghly before buying.....best source of info is google.....