Looks like the nearest Sirius repeaters are near Pearl River NY and Paramus NJ. But these repeaters are at least 7 mi away from Suffern, so they may not be able to penetrate your office's tinted windows--and they're not necessarily aimed in your direction. Sirius says that they're working on...
Hacking your own Sirius antenna is difficult--receivers give an "antenna error" if they can't detect an antenna with the proper load (as the antennas have a preamp).
Even though this is a satellite-centric forum, is there a Sirius ground repeater nearby your office? Can you check via the signal...