Buying Black Canvas

hi all, as usual im looking for help here, im trying to find out where to buy roughly 4 metres by 3 of durable black canvas, the reason for this is i had my soft top slashed and was informed that a new canvas top would cost pretty much more than my car was worth, therfor i used the power of mental thinking and remembered i was quite good at sewing, thought i may give it a whirl myself, can anyone help my broke ass? as usual any of your help is really appreciated.... as i said its 4x3 black canvas im seeking but here in wexford theres no crafts shops or providers that i'm aware of.... thanks all
-lar