Yeah, only the 18-55mm that came with the camera. Given I'm just a few months old on this, I wasn't sure if it is a good idea to start buying new lens already, but I guess if it is a matter of time, sooner or later I'm gonna have to.
You have a few options and each is kind of based on your preferences. Your kit lens might be showing its limitations by having issues like hunting for focus in lowlight. You can replace it with a better lens with similar focal lengths but lower aperture and better build quality. This is probably the least sexy option because you are replacing it with something familiar.
The next is to delve into the primes which is what you seem to be leaning towards. Better quality and better apertures but you lose some of the nice ability to adjust focal length and instead have to think about composing your pictures based on where you stand. That's a great tool and skill to learn.
The third, is if you think you want to expand your zoom capabilities. Buying a good zoom lens that starts at the low end where your kit lens is at it's highest and then goes up to about 250-300mm. This gives you plenty of reach all through the spectrum.
It seems like your ready to dive into primes though so if you can only afford one lens and want to buy a good one the Nikon 1.4 seems like a good choice.
Take into consideration what you like to shoot and tailor your lens purchase to that. Also, if you shoot a lot of short focal length on your kit (18mm range) then maybe a 50mm isn't for you.
I can tell you I've been through a lot of fumbling purchases in my short time doing this and finding the right path is hard so don't worry if you buy something you don't like. Renting is also a good way to check out equipment you are unsure of.