it takes about 35 minutes to get to that place from any place in DHA, shortcut it from civic center and then gharibabad phaatak and you are already there.
load up your car and pay whatever cheap prices he asks.
the other option is that you can visit old karachi like jodia bazar or lee market - they have massive warehouses of such - but its a herculean effort threading your car there - I had troubles with a motorcycle.