First, about homeopaths. Naturpaths do use homeopathy, but most are not what I would call homeopaths. Most homeopaths are MD's who did graduate work in homeopathy. They went to a homeopathic college and are extensively trained in the art and science of prescribing homeopathic medicines. Look for a web directory of holisitic doctors and you might find what you're looking for. I might do some research for you myself.
A good homeopathic guide to start with is Homeopathic Medicine at Home by Maesimund B Panos. This is the book that got me started. There are many very good books about homeopathy for just pregnancy and childcare, most good healthfood stores have them, and if not, try Borders or Barnes and Noble. Also, if you are interested in using homeopathy regularly, try to find a good Materia Medica with a repertory. The Materia Medica is an extensive list of remedies and their actions. A repertory is a symptoms guide which helps you find the correct remedy.
As for chiropracters, try searching the web for a chiropractic organization that has a directory. Also, any good chiropracter should be able to provide you with a list of references of people who have used their services. You can call them and ask their opinion about the doctors skill with children. Also, try to find one that has been in practice for a long time. Ask everyone you know if they go to a chiropracter and what they think about theirs.
And remember, don't be afraid to use the colic remedy, it won't hurt her and it will probably help. You're just more likely to get better results by using a well chosen single remedy.
I almost forgot, a very good websight for homeopathy is abchomeopathy.com.
Edit. I just found a good websight to help you search for alternative practitioners. It's chiropracter-finder.com. You can search for any type of practitioner including homeopaths.