antenna gain & signal power

Hello!

I need to find out the antenna gain of the WLAN cards in my laptop and phone, as well as the transmitted signal power.
I have an Intel® PRO/Wireless 3945ABG in my laptop and an Atheros AR6003 in my phone. Can someone help me with this?

Thanks!

Since nobody answered me I tried to compute the gain myself, but I've reached a dead end again.

I found that the unknown gain of an antenna can be computed with the formula:

Gain [dBi] = ReferenceGain [dBi] + (MeasuredLevel [dBm] - ReferenceLevel [dBm] )

The notations are:

Gain - unknown gain (of laptop or phone antenna)
ReferenceGain - gain of a reference antenna
MeasuredLevel - signal strength (in dBm) from the antenna of unknown gain
ReferenceLevel - signal strength (in dBm) from the reference antenna, measured in the same conditions as MeasuredLevel

I've used a reference antenna with a 3 dBi gain.

My values are:
ReferenceGain = 3 dBi
MeasuredLevel = -75 dBm
ReferenceLevel = -39 dBm

and after the computations the gain is Gain=-33 dBi (negative gain !!!)

I don't think these results are correct.

Can someone tell me what am I doing wrong?
Or even better can someone tell be the gain of these antennas?

Thanks!