If you’re thinking about replacing the heater, I’m going to stick you with more reading!
Most heaters out there will accept a powered anode. I suggest you read Choosing a Water Heater and the Best Water Heater in the Basics section. In particular, make sure the heater has good insulation. I’ll answer more questions, but a central focus of my site is for people to empower themselves by understanding water heater issues that are important to them.