The N62 engine in your car does not produce any manifold vacuum. The brake booster operates off manifold vacuum. To remedy this the bank 1 (right side of the engine) has en externally mounted vacuum pump that is driven by the exhaust camshaft. The vacuum pump tends to leak oil from the front cover and BMW does not offer a seal for the repair. An oil filter o-ring from a 2007 3 series will work on the vacuum pump on your car. Any competent independent repair shop should be able to complete this for a fraction of the cost of a replacement pump.
The entire repair at my shop is typically in the $250 range.