Marion, what quality of sound are you looking to get out of your guitar? If you are looking for an "acoustic/electric" sound, and want to experiment with effects, then by all means get the acoustic amp. If you want a more "natural" guitar sound, you might choose to go with a small PA, mic the guitar, and forget the pickup.

I've tried pickups for years (fishman, baggs, b-bender, pickup the world, ect.) and have yet to find anything that sounds as good as a mic'd guitar. I've even gone the pickup/internal mic route ( fishman blender and rane ap-13 preamps) and found them lacking. This last year I removed all the pickups from my instruments and have been much happier with the results.

If you do decide to try the microphone method, make sure you purchase good mics. The afore mentioned 58's and 57's sound great but might be somewhat feedback prone. The AKG C1000S condenser (with the hypercardioid adaptor installed) will give much more gain before feedback. The AKGs are also "warmer" to my ears than most other condenser mics.

Most good vocal mics work well on both fiddle and voice, you just have to learn how far away from the mic to sing to balance the violin and voice. My present fiddler plays very loud and has to move in to sing. One of my previous fiddlers played with a soft touch and had to back out of the mic when she sang!

Good luck on your decision, hope all the various advise helps!

Mike