I have a Sony Ericsson GC83 Edge/GPRS PC Card for my laptop. Are you aware of any antennas/boosters which will help improve/boost the wireless reception of this?
The GC83 is a triple band (850/1800/1900 MHz) US GSM (Global System for Mobile Communications) cellular modem. Adding an external cellular antenna to improve your signal requires obtaining a phone adapter cable with an FME Male antenna connector to connect to a cellular antenna with an FME Female connector. Something like a short 12-inch Wilson #355011 cable. Rumour has it that the GC83's stock antenna jack is prone to weaken and break. If you decide to get the external antenna/pigtail solution, you might want to wrap some electrical tape around the card connector and cable to support it.
Stock replacement antennas that fit directly into the card are available ($20-$30 USD), but won't change your signal strength. The ARC Wireless Solutions Freedom Cell Phone Antenna claims omni-directional coverage in the 800 MHz to 3.5 GHz range with 1dB of gain.
Not recommended: A length of 65mm(2.6") long AWG 20 wire [.75mm (.03") in diameter] will serve as an emergency antenna for Sony-Ericsson's GC83 PC Card when you break the factory one. Strip less than 1mm (.040") of one end and bend the wire in an 'L' like the original antenna. Plug it in to the card's antenna jack.