wireless signal through metal bubble wrap

When my cousin built his new home he lined the floor with metal bubble wrap material to keep the heat in the downstairs. He had the cable company install in the basement and used a wireless router from the vendor. Needless to say there is no signal upstairs.

He has since passed away and his widow is asking me how she can extend the wireless signal to the upstairs.

I'm thinking she needs to have another router upstairs and have it cabled to the router downstairs. She lives 3 hours away from me so I'm trying to find a simple way for her to get this done without me having to drive down one weekend. I'm also far from an expert in this field.

Can anyone recommend a simple solution? She lives alone.

Thanks