R.L.
Mandi hit the nail on the head. Most pediatricians reccomend starting whole milk at around age 1. You definitely want to mix it with formula or reast milk and introduce it gradually.
As far as weaning, you may not want to stop pumping cold turkey. Since it can become very uncomfortable to not pump or nurse when you are used to doing so. I would suggest gradually pumping less, and then stopping. Before you are ready to stop pumping being mixing part breast milk part formula and then you can mix in whole milk and make the transition easier on baby's tummy. If you baby is already feeding himself, transitioning to a sippy cup from a bottle is probably the easiest way to wean. It is harder to wean if baby is used to going to sleep with the bottle. One thing that may work is to only put water in the bottle, and put milk/formula in the sippy cup. Eventually they will get the idea that the bottle is no longer the milk supply!
Don't stress about it, all babies wean at different times.
Good luck!