Buy Trousers

I am looking for someone to make Trousers for golf. I want them made in a cotton with maybe a little bit of spandex or similar to give a little stretchability. I will be looking for vibrant colours, lime green, pink, yellow, red and white.Sizes 32\", 34\", 36\", 38\", 40\"25 of each size and colour = 625 pairs of trousers.As my wife and I are just setting up our Golf Apparel company in Australia we need to know cost of manufacture and time to manufacture. I hope you can help with this enquiry.