If you're only going to be syncing with the network in your house (and you always park in roughly the same spot), then get yourself a nice powerful directional antenna, and put it in your house, pointing towards the car

Or you couple place it in the car pointing at the house, if you always park in the same place, pointing the same way
If you will want to try to pick up multiple networks, from all around, get an omni-directional antenna, as it will increase your range in all directions.
Garry