Best wireless laptop card?

I've had sporadic problems with our laptop's wireless card. (note: this is
not a PC Card/PCMCIA, it's the newer tiny card that fits in the bottom of
the laptop) Often it connects, but then I can only occasionally download
things or view web pages. Many times it cuts out after a couple of minutes.

I downloaded and installed the latest drivers, then ran the diagnostics
again. It always says there is a problem with the wireless card's internal
memory, which might explain the sporadic connections, even when the signal
is strong.

Can anyone recommend a quality replacement card? In this case, I'm
looking for quality, not the lowest price. Thanks!