A ceramic is the easiest option, only has to be low wattage and doesn't affect any lights you might have in your set up.
Swell do their own range just as good as any other.
Swell Ceramic Heat Emitters | Swell Reptiles
Heat guards can be expensive from shops (For some reason). There are people that make them for cheaper on the forum .
A dimmer or pulse stat is a must, these ceramics can get seriously hot and an on/off stat will make you're temps irregular and shorten the ceramics lifespan, or possibly blow it.
Make sure you're also using a digital thermometer underneath the heat source so you're sure of the temps you're getting.
All in all, not exactly a cheap transition. But the good news is there's no rush. Your crested will be fine for the time being.
If you have any concerns, doubts or worries about your animals health always consult a qualified veterinarian (with the necessary experience).
Nobody can properly diagnose an animal based on descriptions and photos. Especially when those animals, such as reptiles, have a small list of visible symptoms than can be found across a large range of problems.
Always see a vet. Don't let strangers on the internet make you do something you'll regret. They won't take responsibility.