[amymnc]

Probably a speed light or a one-light Alien Bee set-up would suit you well.
Here are two books on lighting that I really enjoyed. The second one is much more technical and a longer read. I find myself referring back to that one very often.

Amazon.com: Beginner's Guide to Photographic Lighting: Techniques for Success in the Studio or on Location (9781584281337): Don Marr: Books

Amazon.com: The Complete Guide to Light & Lighting in Digital Photography (A Lark Photography Book) (9781579908850): Michael Freeman: Books