I'm sorry to hear about your fire alarm panel.
The first answer is no, I don't know where to get any parts to this panel.
The bigger picture, though, is that even if parts are found for the panel, fixing the panel is only a short term solution to the problem. All electronics, including fire alarm panels, break down. Right now it sounds like you don't have backup power for the fire alarm panel.
Sooner or later, something else will break down and you won't be so lucky.
If the next breakdown is the display, or the CPU, or maybe a loop controller, you won't have a fire alarm system. When that happens, replacement of the full fire alarm system will have to be done on an emergency basis. Many extra costs are involved including Fire Walks, and overtime for your company as well as overtime for the fire alarm company (passed on to you) will be included in the emergency.
When the fire alarm panel is replaced in an emergency, you don't even have a chance to shop around for a good fire alarm company, you're stuck with the first company ready to do an emergency replacement.
Yes, continue looking for a part for the fire alarm panel, but get that fire alarm system replaced very soon or plan on paying the huge extra costs of emergency replacement of the fire alarm system.