I'm staying at my sister's place for a few months. She has an HP Pavilion PC laptop and an ethernet/USB cable modem without Wi-Fi. As a lifelong Apple user, I know nothing about Windows or PCs. What's the best way to share the internet from the PC *wirelessly* to my rMBP? I've tried setting up an ad hoc computer network and it works, but the connection seems to crap out within 5 minutes. I'm hoping for an always-on solution rather than constantly needing to disconnect and re-connect. Thanks in advance for all help.