Do you know whether the amplifier SSW-10 still works? If so, then you might consider another 10" driver.
You could contact Infinity about whether they sell a new driver or recommend a third-party driver. If Infinity (or someone else) could give you the Thiele/Small (T/S) parameters, then you might go to Parts Express (or some other reputable company) to find a 10" driver with very similar T/S parameters as a replacement.
The service manuals for JBL/Infinity subwoofers typically do not give the T/S parameters. They only give the recommended driver.
If this seems like too much of a hassle, then you might consider one of the 12" recommended subs in the ~$200 range such as BIC F12 or Premier Acoustic PA-120.