dampproofing a house

Here is a picture of the bottom bit of the house.
It has a "damp proof course" which has been put in the bricks rather than the mortar by the previous owner or even the one before that.
It has then had bitumen type paint put on the lower bit, which  we think was trapping rising damp. Cobbles used to be up to the wall but hubby has taken 1 row away.
Should we brush away the black stuff and put in a damp course lower down.?
Should we cement between the house and slabs sloping away from the house and add shingle? How deep should the shingle be?

make sure there's nothing in between the damp proof course and the wall above it, "bridging" which will allow the damp to rise and cross over to the brickwork above, I wouldn't put bitumen under the damp course  the reason being if damp comes up it will be a lot better for the wind ans sun, and warm air to do the job of drying the brick work out under the damp line, if you do its a barrier to keep the damp within the wall as there's no escape