My first question: what's the mileage on that shock? - It appears that most OEM shocks are not designed to last much longer than 20-25K miles, before the damping oil has deteriorated so much that there is no damping left.
One option is to get a used aftermarket shock that can be renovated (and tuned to your weight/riding style). If it was an old bike this might have been your only option for upgrading the shock, as many aftermarket companies stop producing for older generations.
Most aftermarket shocks (Öhlins, Penske, WP etc) can be renovated for USD100-150. I'm not in the US, so I'm not sure of the cost.