US Acoustic uxs2100

Unfortunately in your situation it would be better if you had either two of your subs, or one single voice coil sub.  This amp (and most other amps) is not stable when bridged to 2 ohms, and that's what you'd need if you ran your voice coils in parallel.  So your only other option is to wire them in series, but as you probably know the power output in series is substantially less.

Actually technically you could run this one sub off of one of the amp's channels, and you'd have 150 watts.  but you'd still end up using only half of the amp's power.