You may be able to conect a wireless access point to the PC, then access that from your laptop.Not sure if connecting a wireless router to the home pc could work. Yeah they 3gb cap but they won't charge for going over, bit odd but thats what i was told by sister bf.
You may be able to set the Access point to use the PC's internet connection.
Not done that though, but it would only seem to be a matter of inbound and outbound protocol setups.