It's okay, most people do get burned when starting out. Still, don't toss it, because it will still perform as well as that cheaper stuff I listed, and if it is keeping you off of cigarettes, it's still worth it

I've seen several mentions of VaporFi around lately and it really gets to me, mostly because equivalent equipment is so much more inexpensive and generally speaking higher quality.
As to your question:
Almost all of the standard EGO style batteries that aren't variable output somewhere between 3.5 and 3.8 volts, with the standard being 3.7. I'd bet the one you have is outputting 3.7ish.
"Twist" and "Spinner" style batteries have a small dial at the bottom that you can adjust the voltage output, usually between 3.3 volts and 4.8 volts. I've found that Nautilus' perform best on these kinds of batteries between 4.2 volts and 4.8 volts (personally I always run at 4.8 if I'm using a spinner). Obviously, with more power going to the heating element, more vapor and warmer vapor is the result. BVC coils perform well all the way up to 6 volts though, so even at 4.8 volts you may not get a "warm" vape, but certainly warmer than 3.7 or 3.8 volts that you're getting now.
The Twist and Spinner style batteries are one step up from what you are using. There are of course more powerful options available, but that's where the price starts to jump up. Twist/Spinner style is still an affordable option.