That would never work, since the antenna then would be inside the PCMCIA cage.
You'd have no or almost no connection whatsoever.
You could do some DIY.
Find an antenna wire that you could install under the (plastic) palmrest, or rather, inside the LCD.
Then lead the wire to the pcmcia cage.
You need to open up the wifi card, and cut off the outside (sticking out) part.
Then connect the internal antenna wire to the connector in/on the wifi card.
I've never tried this, but that seems the only solution.
Alternatively, there are USB wifi dongles, which are smaller than the PCMCIA cards.
I don't know that machine.
Maybe you could replace the modem card with a wifi card, using the antenna as described above (but you'd need 2 antenna wires now).
It seems to be possible, check this post: viewtopic.php?f=6&t=90827