You will want to find a broad spectrum herbicide that is specially formulated to kill clover and other broad-leaf weeds. In most herbicides, the active ingredient will be a chemical called MCPP. It shouldn't kill your grass, but after the clover is dead, you'll want to replant the area with grass to fill it in.
I would wait until spring around march when it starts to sprout. The spray with Round-Up. This will prevent the plant from sprouting. The closer you get to the root area the better. It will turn brown and then you can pull it out. Remember when it starts to bloom, then Round-Up.