Hello, my name isXXXXX appreciate you taking the time to ask a question about your car. There are several good products on the market for this. The best one I have used is ORS (oil stain remover) from Seal Krete. It pours onto the stain as a liquid and penetrates the concrete and actually pushes the oil up and out. These are several products on the market like this so it should not be hard to find. If you cannot find it let me know and I will send you over a link online to find some.
Here you go. It is pretty much the same product from a different manufacturer.