Extending wireless internet signal?

[johnathon r]

I am trying to extend my wireless internet range so that my sister who lives on the same property but about 3-400 feet away can share my internet. I currently have a Netgear N600 router which has no external antennas on it here at my house...She can not get online as the signal is can not reach. I cant even access my router on my phone when im in her house. I am wondering how can i extend my range. Do i need to buy a new router for here at my house, possibly one with antennas on it? Running a cat 5 cable from house to house is a hassle as the only person that can do it seems to never have the time and i can not physically do it, because of being wheelchair bound. We both have metal roofs on our homes but i was told that wouldnt make much of a difference. Any concrete advice would be appreciated. please no BS answers. Need to get this done as soon as possible.
I repeat, i am trying to get this done as soon as possible and running cat 5 or cat 6 cable from house to house would take to long due to no time for the only person that can physically do it.