I may be mistaken but, I don't think you can do what you're asking. The SIM slot is to access a cellular carriers network, and as such you can surf the internet. The SIM would have to be activated by your carrier.
There are many applications that allow you the "make a video call" to a second computer/laptop but not to a traditional cell phone.
Laptops just don't have the hardware to transmit on cellular airwaves other than data.
Regards,
Louis