Your options as to how you will be able to connect are going to be determined based on what equipment she has in place.
If she has a wireless network, then you should be able to connect, but of course not with your passphrase, she will need to provide you with the security phrase in order to connect.
And
Depending on what her ISP has provided in the way of an applicance will determine what you can connect to her modem. Most ISP's provide any number of appliances, so you will need to know if her "modem" is identical to yours or not, if so and she does not also have her own router in place, then assuming she will allow you to do it, you should be able to plug in your router the same as at home but you will likely have to power cycle the...