Reading the data from a glucometer externally with a microcontroller or arduino board
I suggest you to buy Bayer Contour TS that has usb cable and software for windows. If you want to read data by using microcontroller or arduino you must know something about UART (RX,TX).

If you can not do anything just focus on making a glucose meter. I suggest you to try to do Microchip Glucose Meter. It looks easy to do because it's open source so you can read data easily

Hope you got answer.