How do I get rid of scratches made by a scouring pad on my car?

I used a rough edge of a cleaning sponge to get some stubborn dirt off my car. I tried a small area first and this looked ok, so I carried on. When I came to look at it again the next day there were small scuffy scratches on the lower parts of the doors and near the tyres. The scratches are isolated to the doors only and are not all over the car. However, it is noticable. The whole of the affected area is intermitent but probably measures around three quarters of a metre across and half a metre up.

Can I fix the scratches myself or do I take it to a garage/dealership? Can anyone give me a rough figure as to how much this will cost in a garage/dealership?