Yousaf, if you search ebay for TechStream, you will see that you buy it as a USB to OBD dongle plus software.
You need a 32 bit Windows OS equipped laptop (to make it less of a headache with getting the USB serial drivers working), install the software and drivers on the laptop, connect the OBD dongle to car and to PC and run the TechStream software.
Have a look at this video, I've not watched it (I'm at work) but it seems to show how you how to connect and use TechStream