I don't know the street name but If you know M.P. Trader (after which Sana roundabout comes) oppst. road you will find several car accessories shop. Go there and you will find what you are looking for. If not then go to Mattar Kadeem (Near Al Habeeb Restaurant - Turkish) there are few car accessories shops and they have all these types of stuff also.

Regarding Cost it is difficult to tell since there are so many brands/ unbranded items and the price depends on the quality of the item.