If the computer supports a port replicator style docking station like this one, then all you have to do is get a dock (which could be permanently mounted) and hack it up to a relay from your ignition.
HI. I presume the comport in question for "wake up on ring" is the comport for the modem where the telephone cable plugs into?. I do not have an RS232 port on my laptop as it is an acer 5610. So for a newbie to understand the concept of waking up the pc from a "wake up on ring" solution is that I need to pulse a signal to this port to wake up the pc?.