Story of Christianity by Justo Gonzalez is really great if you're wanting the basic broader history of the church. It's a textbook, just it's so well written it doesn't feel like you're reading a textbook.
You might really appreciate this book by Paul Knitter, “Without Buddha I Could Not Be Christian”…
Many have found Buddhism excellent at helping one move beyond the familiar road signs of religion (the symbolic) to the spiritual substance found in the destination of true spiritual experience. I really loved reading “Siddhartha” by Herman Hesse as well. It helped open my world a bit.