Can someone tell me if it possible for me to use the bass sounds in Kontakt to add just playing a regular bass?  I have a keyboard, but I would rather actually just play my bass but get the same effect?  

Use a guitar to midi converter software and play it on a guitar. The midi output would then be sent to Kontakt for the bass sounds.
I know, the guitar is not a bass as you requested but it would be closer than using a keyboard.
 
example software:
http://www.jamorigin.com/products/midi-guitar/
 
 

One thought I had was converting the audio to midi and then would it be able to play the midi sounds for the bass?

nathanielleemaloney
One thought I had was converting the audio to midi and then would it be able to play the midi sounds for the bass?

If the audio track is clean and played consistently it can work.
You will probably have to do some editing of the midi to get rid of false notes and such.
Melodyne can do the audio to midi conversion for you.
Give it a try!  Trying things like this is the best way to learn.

Melodyne does a pretty good job of converting audio to MIDI. But you have to help it, and you're probably going to have to do a little MIDI editing afterwards. 
 
First it's important when playing for Melodyne that you play as cleanly as possible. So probably best to leave out any slides, bends or vibrato. Secondly I believe it is a good idea to roll off the highs of your instrument as much as possible before Melodyne hears it. The reason is that Melodyne often gets confused by harmonics and you may find harmonics converted to MIDI notes unless you roll them off. The best way to do this is to turn down the tone pot of your guitar all the way, or I guess you could apply a low pass filter in Sonar and print the clip to audio with the filter. 
 
Note I'm not 100% certain about the benefits of rolling off the highs for Melodyne, but in my experience it does seem to result in a better conversion. 
 
And then lastly you're going to want to check the MIDI for any bum notes and work on the velocities yourself because in my experience what Melodyne gives you in terms of velocities is almost never what you want. 

Every time I've tried that it's been a hassle. Slides, bends and vibrato don't translate well. And you have to record the bass direct; amping yields too much distortion that can confuse Melodyne or whatever software you're using.
 
Don't dismiss the possibility of playing bass on a keyboard, even if your keyboard skills are minimal. As a bass player, you might be surprised at how well you adapt. Just as drummers can be the best drum sequencers, bass players quickly figure out how to translate keyboards to believable bass parts. You don't have to be adept at the keyboard. You'll be recording MIDI, not audio, and can therefore correct any mistakes before rendering. You can record the part at half speed if necessary. In the end, you'll have a lot of fun trying out different sources for the audio such as synthesizers and sample libraries, and layering multiple sources for effects you'd never achieve with your bass.

A slightly different approach that I've used successfully in the past is to sing the notes.  Then use Melodyne to convert to midi.  I'm a far more facile singer than I am bass player!!

bitflipper
 
Don't dismiss the possibility of playing bass on a keyboard, even if your keyboard skills are minimal. As a bass player, you might be surprised at how well you adapt. Just as drummers can be the best drum sequencers, bass players quickly figure out how to translate keyboards to believable bass parts. You don't have to be adept at the keyboard. You'll be recording MIDI, not audio, and can therefore correct any mistakes before rendering. You can record the part at half speed if necessary. In the end, you'll have a lot of fun trying out different sources for the audio such as synthesizers and sample libraries, and layering multiple sources for effects you'd never achieve with your bass.

being a bass player at heart this IMHO is the best advice given here and completely reflects my experience, yet I would scratch the part about playing half speed. I'd do the other extreme i.e. no quantizing at all (it's bass, so this essentially is a rhythm track). I would use a cost effective (trying to avoid the word "cheap" here) keyboard that you like for playing bass lines (it's most likely not the fully weighted piano keyboard), enjoy the fun of playing bass lines with different sound sources/synths and play until you like the bass lick, then record and comp. Stay away from quantizing and don't spend too much time in the piano roll editing (for bass I usually limit myself to deleting stray notes, although with some good bass VSTs, these almost silent stray notes actually add some character).
 
using this approach I have actually developed some bass lines for songs that I wouldn't have playing the real bass, but they translate well to the instrument i.e. they sound really cool and are indeed fun to play on the real thing.
 
BTW, as regards K11, I really like the Rickenbacker emu. That actually makes we want to buy a real Rickenbacker.
 
 

there are bass to mid convertors
 

Ham N Egz
there are bass to mid convertors
 

interesting tool. unfortunately reviews are not so great and direct order from company only ... otherwise I might have tried it for the fun of it