Try the backside of the connector. You can buy one, or make one yourself. The cabling for the OBDii connector runs to the back of the connector, remove the connector, cut the wires & solder in an extension with a DB25 female connector. Keep the old OBDii connector & solder that up to another DB25-M for the garage.
CAR SIDE PC SIDE
[CAR]=======/ DB25-F/ /DB25-M/====[PC]
[CAR]=======/ DB25-F/ /DB25-M/====/CUT-OFF OBDII/
Personally I'd spend the US$20 on an adapter from http://www.scantool.net/
Also check out http://www.elmelectronics.com/, I purchased my OBDii to RS232 chip there & build my code read with an Atmel 128, super easy!