Hi. I dont know what router or device you are currently using, but chances are if it performs better outside, a good router that supports external antennas will give you good results. My issues are with congestion, but even then, having aimed my external antenna with the help of the optimise tool, i at least have very stable signal now. The B315 is a great choice as it also has 2 SMA connectors, so you will get full benefit from a MIMO antenna like the XPOL range.
Factors outside your control notwithstanding (congestion), you should have good results.