How much do you want to spend? I just bought an external antenna to try it out for about $30.00.
http://www.amazon.com/Blurex-Wireless-N-Network-performance-increase/dp/B00KXAFYZS/ref=sr_1_3?s=pc&ie=UTF8&qid=1443049374&sr=1-3&keywords=long+range+wifi+antenna

I will be getting it tomorrow and will let you know how well it works for me.

Greg