Hi PVINIT,
Please note that all our products are guaranteed to work only for the official nopCommerce release and not custom builds.
I see that you have added a new parameter and that is why the Nop Ajax Filters throw an error as they rely on this method. Even if you make the parameter to be an optional, this will not work as this is a breaking change.
One possible solution is to create your own method that accepts the new parameter, within this method call the unmodified PrepareProductOverviewModels function and then execute your custom logic. Thus both the Nop Ajax Filters and your custom logic will work.
Hope that helps!