Two things will record your nylon-string with a better sound:
* An expensive mic. The more you pay for a mic, the more sensitive it is, more or less. A condenser sounds better than a dynamic. A ribbon sounds better than a condenser (or so I've heard, my budget not having extended to ribbons yet, but you should hear the old hands rave about them).
* Two mics. Two mics produce a clearly better sound than one mic.
Explore the Microphone Forum page to get ideas about brands.
BTW, how well does the Takamine keep in tune all the way up the fretboard?